diff --git a/pom.xml b/pom.xml
index e3dbf69..08d6461 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
 
     <groupId>com.andrewlalis</groupId>
     <artifactId>perfin</artifactId>
-    <version>1.11.0</version>
+    <version>1.12.0</version>
 
     <properties>
         <maven.compiler.source>21</maven.compiler.source>
diff --git a/src/main/java/com/andrewlalis/perfin/control/EditTransactionController.java b/src/main/java/com/andrewlalis/perfin/control/EditTransactionController.java
index 9ab3fc3..2f44e97 100644
--- a/src/main/java/com/andrewlalis/perfin/control/EditTransactionController.java
+++ b/src/main/java/com/andrewlalis/perfin/control/EditTransactionController.java
@@ -13,12 +13,12 @@ import com.andrewlalis.perfin.view.component.AccountSelectionBox;
 import com.andrewlalis.perfin.view.component.CategorySelectionBox;
 import com.andrewlalis.perfin.view.component.FileSelectionArea;
 import com.andrewlalis.perfin.view.component.TransactionLineItemTile;
+import com.andrewlalis.perfin.view.component.validation.AsyncValidationFunction;
 import com.andrewlalis.perfin.view.component.validation.ValidationApplier;
 import com.andrewlalis.perfin.view.component.validation.ValidationResult;
 import com.andrewlalis.perfin.view.component.validation.validators.CurrencyAmountValidator;
 import com.andrewlalis.perfin.view.component.validation.validators.PredicateValidator;
 import javafx.application.Platform;
-import javafx.beans.binding.Bindings;
 import javafx.beans.binding.BooleanExpression;
 import javafx.beans.property.*;
 import javafx.beans.value.ObservableValue;
@@ -41,6 +41,7 @@ import java.time.DateTimeException;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
 import java.util.*;
+import java.util.concurrent.CompletableFuture;
 
 import static com.andrewlalis.perfin.PerfinApp.router;
 
@@ -57,6 +58,7 @@ public class EditTransactionController implements RouteSelectionListener {
     @FXML public TextField timestampField;
     @FXML public TextField amountField;
     @FXML public ChoiceBox<Currency> currencyChoiceBox;
+    private final BooleanProperty basicTransactionInfoValid = new SimpleBooleanProperty(false);
     @FXML public TextArea descriptionField;
 
     @FXML public HBox linkedAccountsContainer;
@@ -132,11 +134,13 @@ public class EditTransactionController implements RouteSelectionListener {
         var linkedAccountsValid = initializeLinkedAccountsValidationUi();
         initializeTagSelectionUi();
         initializeLineItemsUi();
+        initializeDuplicateTransactionUi();
 
         vendorsHyperlink.setOnAction(event -> router.navigate("vendors"));
         categoriesHyperlink.setOnAction(event -> router.navigate("categories"));
         tagsHyperlink.setOnAction(event -> router.navigate("tags"));
 
+        basicTransactionInfoValid.bind(timestampValid.and(amountValid).and(currencyChoiceBox.valueProperty().isNotNull()));
         var formValid = timestampValid.and(amountValid).and(descriptionValid).and(linkedAccountsValid);
         saveButton.disableProperty().bind(formValid.not());
     }
@@ -313,6 +317,49 @@ public class EditTransactionController implements RouteSelectionListener {
                 .attach(linkedAccountsContainer, linkedAccountsProperty, currencyChoiceBox.valueProperty());
     }
 
+    record BasicTransactionInfo(LocalDateTime timestamp, BigDecimal amount, Currency currency) {}
+
+    private BasicTransactionInfo getBasicTransactionInfo() {
+        if (!basicTransactionInfoValid.get()) return null;
+        return new BasicTransactionInfo(
+                DateUtil.localToUTC(parseTimestamp()),
+                new BigDecimal(amountField.getText()),
+                currencyChoiceBox.getValue()
+        );
+    }
+
+    /**
+     * Initializes the duplicate transaction validation, which operates on the
+     * basic transaction properties: timestamp, amount, and currency. We listen
+     * for changes to these, and if they're all at least valid, we search for
+     * existing transactions with the same values.
+     */
+    private void initializeDuplicateTransactionUi() {
+        Property<BasicTransactionInfo> txInfoProperty = new SimpleObjectProperty<>(getBasicTransactionInfo());
+        basicTransactionInfoValid.addListener((observable, oldValue, newValue) -> {
+            if (newValue) {
+                txInfoProperty.setValue(new BasicTransactionInfo(
+                        DateUtil.localToUTC(parseTimestamp()),
+                        new BigDecimal(amountField.getText()),
+                        currencyChoiceBox.getValue()
+                ));
+            } else {
+                txInfoProperty.setValue(null);
+            }
+        });
+        AsyncValidationFunction<BasicTransactionInfo> validationFunction = info -> {
+            if (info == null) return CompletableFuture.completedFuture(ValidationResult.valid());
+            return Profile.getCurrent().dataSource().mapRepoAsync(
+                    TransactionRepository.class,
+                    repo -> repo.findDuplicates(info.timestamp(), info.amount(), info.currency())
+                )
+                .thenApply(matches -> matches.stream().map(m -> "Found possible duplicate transaction: #" + m.id).toList())
+                .thenApply(ValidationResult::new);
+        };
+        new ValidationApplier<>(validationFunction)
+                .attach(descriptionField.getParent(), txInfoProperty);
+    }
+
     private void initializeTagSelectionUi() {
         addTagButton.disableProperty().bind(tagsComboBox.valueProperty().map(s -> s == null || s.isBlank()));
         addTagButton.setOnAction(event -> {
@@ -403,12 +450,10 @@ public class EditTransactionController implements RouteSelectionListener {
             }
         });
         BooleanProperty lineItemsTotalMatchesAmount = new SimpleBooleanProperty(false);
-        lineItemsTotalValue.addListener((observable, oldValue, newValue) -> {
-            lineItemsTotalMatchesAmount.set(newValue.compareTo(amountFieldValue.getValue()) == 0);
-        });
-        amountFieldValue.addListener((observable, oldValue, newValue) -> {
-            lineItemsTotalMatchesAmount.set(newValue.compareTo(lineItemsTotalValue.getValue()) == 0);
-        });
+        lineItemsTotalValue.addListener((observable, oldValue, newValue) ->
+                lineItemsTotalMatchesAmount.set(newValue.compareTo(amountFieldValue.getValue()) == 0));
+        amountFieldValue.addListener((observable, oldValue, newValue) ->
+                lineItemsTotalMatchesAmount.set(newValue.compareTo(lineItemsTotalValue.getValue()) == 0));
         BindingUtil.bindManagedAndVisible(lineItemsValueMatchLabel, lineItemsTotalMatchesAmount.and(lineItemsProperty.emptyProperty().not()));
 
         // Logic for button that syncs line items total to the amount field.
diff --git a/src/main/java/com/andrewlalis/perfin/control/TransactionsViewController.java b/src/main/java/com/andrewlalis/perfin/control/TransactionsViewController.java
index 068c200..d2018b6 100644
--- a/src/main/java/com/andrewlalis/perfin/control/TransactionsViewController.java
+++ b/src/main/java/com/andrewlalis/perfin/control/TransactionsViewController.java
@@ -66,6 +66,9 @@ public class TransactionsViewController implements RouteSelectionListener {
             paginationControls.setPage(1);
             selectedTransaction.set(null);
         });
+        // Add a listener to the search field that sets the page to 1 (thus
+        // doing a new search with the contents of the field), and deselects any
+        // selected transaction.
         searchField.textProperty().addListener((observable, oldValue, newValue) -> {
             paginationControls.setPage(1);
             selectedTransaction.set(null);
@@ -185,6 +188,14 @@ public class TransactionsViewController implements RouteSelectionListener {
     private List<SearchFilter> getCurrentSearchFilters() {
         List<SearchFilter> filters = new ArrayList<>();
         if (searchField.getText() != null && !searchField.getText().isBlank()) {
+            // Special case: for input like "#123", search directly for the transaction id.
+            if (searchField.getText().strip().matches("#\\d+")) {
+                int idQuery = Integer.parseInt(searchField.getText().strip().substring(1));
+                var filter = new SearchFilter.Builder().where("id = ?").withArg(idQuery).build();
+                return List.of(filter);
+            }
+
+            // General case: split the input into a list of terms, then apply each term in a LIKE %term% query.
             var likeTerms = Arrays.stream(searchField.getText().strip().toLowerCase().split("\\s+"))
                     .map(t -> '%'+t+'%')
                     .toList();
diff --git a/src/main/java/com/andrewlalis/perfin/data/TransactionRepository.java b/src/main/java/com/andrewlalis/perfin/data/TransactionRepository.java
index 5686a59..812eb32 100644
--- a/src/main/java/com/andrewlalis/perfin/data/TransactionRepository.java
+++ b/src/main/java/com/andrewlalis/perfin/data/TransactionRepository.java
@@ -31,6 +31,7 @@ public interface TransactionRepository extends Repository, AutoCloseable {
     Optional<Transaction> findById(long id);
     Page<Transaction> findAll(PageRequest pagination);
     List<Transaction> findRecentN(int n);
+    List<Transaction> findDuplicates(LocalDateTime utcTimestamp, BigDecimal amount, Currency currency);
     long countAll();
     long countAllAfter(long transactionId);
     long countAllByAccounts(Set<Long> accountIds);
diff --git a/src/main/java/com/andrewlalis/perfin/data/impl/JdbcTransactionRepository.java b/src/main/java/com/andrewlalis/perfin/data/impl/JdbcTransactionRepository.java
index cbc3bdf..6650702 100644
--- a/src/main/java/com/andrewlalis/perfin/data/impl/JdbcTransactionRepository.java
+++ b/src/main/java/com/andrewlalis/perfin/data/impl/JdbcTransactionRepository.java
@@ -153,6 +153,16 @@ public record JdbcTransactionRepository(Connection conn, Path contentDir) implem
         );
     }
 
+    @Override
+    public List<Transaction> findDuplicates(LocalDateTime utcTimestamp, BigDecimal amount, Currency currency) {
+        return DbUtil.findAll(
+                conn,
+                "SELECT * FROM transaction WHERE timestamp = ? AND amount = ? AND currency = ? ORDER BY timestamp DESC",
+                List.of(DbUtil.timestampFromUtcLDT(utcTimestamp), amount, currency.getCurrencyCode()),
+                JdbcTransactionRepository::parseTransaction
+        );
+    }
+
     @Override
     public long countAll() {
         return DbUtil.findOne(conn, "SELECT COUNT(id) FROM transaction", Collections.emptyList(), rs -> rs.getLong(1)).orElse(0L);
diff --git a/src/main/java/com/andrewlalis/perfin/model/CreditAndDebitAccounts.java b/src/main/java/com/andrewlalis/perfin/model/CreditAndDebitAccounts.java
index a98621b..9fd8530 100644
--- a/src/main/java/com/andrewlalis/perfin/model/CreditAndDebitAccounts.java
+++ b/src/main/java/com/andrewlalis/perfin/model/CreditAndDebitAccounts.java
@@ -2,6 +2,14 @@ package com.andrewlalis.perfin.model;
 
 import java.util.function.Consumer;
 
+/**
+ * A simple pair of accounts representing the two possible linked accounts for a
+ * {@link Transaction}.
+ * @param creditAccount The account linked as the account to which the
+ *                      transaction amount is credited.
+ * @param debitAccount The account linked as the account from which the
+ *                     transaction amount is debited.
+ */
 public record CreditAndDebitAccounts(Account creditAccount, Account debitAccount) {
     public boolean hasCredit() {
         return creditAccount != null;
diff --git a/src/main/resources/edit-transaction.fxml b/src/main/resources/edit-transaction.fxml
index 39bc5e9..9f2bfeb 100644
--- a/src/main/resources/edit-transaction.fxml
+++ b/src/main/resources/edit-transaction.fxml
@@ -1,12 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<?import com.andrewlalis.perfin.view.component.AccountSelectionBox?>
-<?import com.andrewlalis.perfin.view.component.FileSelectionArea?>
-<?import com.andrewlalis.perfin.view.component.PropertiesPane?>
+<?import com.andrewlalis.perfin.view.component.*?>
 <?import javafx.scene.control.*?>
 <?import javafx.scene.layout.*?>
-<?import com.andrewlalis.perfin.view.component.CategorySelectionBox?>
-<?import com.andrewlalis.perfin.view.component.StyledText?>
 <BorderPane xmlns="http://javafx.com/javafx"
             xmlns:fx="http://javafx.com/fxml"
             fx:controller="com.andrewlalis.perfin.control.EditTransactionController"