diff --git a/airbyte-server/src/main/java/io/airbyte/server/handlers/helpers/CatalogConverter.java b/airbyte-server/src/main/java/io/airbyte/server/handlers/helpers/CatalogConverter.java
index 6face8f6f35ee..a16ea2b6e6552 100644
--- a/airbyte-server/src/main/java/io/airbyte/server/handlers/helpers/CatalogConverter.java
+++ b/airbyte-server/src/main/java/io/airbyte/server/handlers/helpers/CatalogConverter.java
@@ -22,6 +22,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
+import java.util.Set;
 import java.util.stream.Collectors;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -66,7 +67,18 @@ private static io.airbyte.protocol.models.AirbyteStream toProtocol(final Airbyte
         }
       }
       // Only include the selected fields.
-      List<String> selectedFieldNames = config.getSelectedFields().stream().map((field) -> field.getFieldPath().get(0)).collect(Collectors.toList());
+      final Set<String> selectedFieldNames =
+          config.getSelectedFields().stream().map((field) -> field.getFieldPath().get(0)).collect(Collectors.toSet());
+      // TODO(mfsiega-airbyte): we only check the top level of the cursor/primary key fields because we
+      // don't support filtering nested fields yet.
+      if (!selectedFieldNames.contains(config.getCursorField().get(0))) {
+        throw new JsonValidationException("Cursor field cannot be de-selected");
+      }
+      for (final List<String> primaryKeyComponent : config.getPrimaryKey()) {
+        if (!selectedFieldNames.contains(primaryKeyComponent.get(0))) {
+          throw new JsonValidationException("Primary key field cannot be de-selected");
+        }
+      }
       for (final String selectedFieldName : selectedFieldNames) {
         if (!properties.has(selectedFieldName)) {
           throw new JsonValidationException(String.format("Requested selected field %s not found in JSON schema", selectedFieldName));
diff --git a/airbyte-server/src/test/java/io/airbyte/server/handlers/ConnectionsHandlerTest.java b/airbyte-server/src/test/java/io/airbyte/server/handlers/ConnectionsHandlerTest.java
index aef4ed143c373..5a23f9f128fab 100644
--- a/airbyte-server/src/test/java/io/airbyte/server/handlers/ConnectionsHandlerTest.java
+++ b/airbyte-server/src/test/java/io/airbyte/server/handlers/ConnectionsHandlerTest.java
@@ -5,6 +5,7 @@
 package io.airbyte.server.handlers;
 
 import static io.airbyte.server.helpers.ConnectionHelpers.FIELD_NAME;
+import static io.airbyte.server.helpers.ConnectionHelpers.SECOND_FIELD_NAME;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -353,6 +354,47 @@ void testCreateConnectionWithSelectedFields() throws IOException, JsonValidation
         verify(configRepository).writeStandardSync(standardSync);
       }
 
+      @Test
+      void testFieldSelectionRemoveCursorFails() throws JsonValidationException, ConfigNotFoundException, IOException {
+        // Test that if we try to de-select a field that's being used for the cursor, the request will fail.
+        // The connection initially has a catalog with one stream, and two fields in that stream.
+        standardSync.setCatalog(ConnectionHelpers.generateAirbyteCatalogWithTwoFields());
+
+        // Send an update that sets a cursor but de-selects that field.
+        final AirbyteCatalog catalogForUpdate = ConnectionHelpers.generateApiCatalogWithTwoFields();
+        catalogForUpdate.getStreams().get(0).getConfig()
+            .fieldSelectionEnabled(true)
+            .selectedFields(List.of(new SelectedFieldInfo().addFieldPathItem(FIELD_NAME)))
+            .cursorField(List.of(SECOND_FIELD_NAME));
+
+        final ConnectionUpdate connectionUpdate = new ConnectionUpdate()
+            .connectionId(standardSync.getConnectionId())
+            .syncCatalog(catalogForUpdate);
+
+        assertThrows(JsonValidationException.class, () -> connectionsHandler.updateConnection(connectionUpdate));
+      }
+
+      @Test
+      void testFieldSelectionRemovePrimaryKeyFails() throws JsonValidationException, ConfigNotFoundException, IOException {
+        // Test that if we try to de-select a field that's being used for the primary key, the request will
+        // fail.
+        // The connection initially has a catalog with one stream, and two fields in that stream.
+        standardSync.setCatalog(ConnectionHelpers.generateAirbyteCatalogWithTwoFields());
+
+        // Send an update that sets a primary key but deselects that field.
+        final AirbyteCatalog catalogForUpdate = ConnectionHelpers.generateApiCatalogWithTwoFields();
+        catalogForUpdate.getStreams().get(0).getConfig()
+            .fieldSelectionEnabled(true)
+            .selectedFields(List.of(new SelectedFieldInfo().addFieldPathItem(FIELD_NAME)))
+            .primaryKey(List.of(List.of(SECOND_FIELD_NAME)));
+
+        final ConnectionUpdate connectionUpdate = new ConnectionUpdate()
+            .connectionId(standardSync.getConnectionId())
+            .syncCatalog(catalogForUpdate);
+
+        assertThrows(JsonValidationException.class, () -> connectionsHandler.updateConnection(connectionUpdate));
+      }
+
       @Test
       void testValidateConnectionCreateSourceAndDestinationInDifferenceWorkspace() {
 
diff --git a/airbyte-server/src/test/java/io/airbyte/server/helpers/ConnectionHelpers.java b/airbyte-server/src/test/java/io/airbyte/server/helpers/ConnectionHelpers.java
index 53c199c198927..223135d04669c 100644
--- a/airbyte-server/src/test/java/io/airbyte/server/helpers/ConnectionHelpers.java
+++ b/airbyte-server/src/test/java/io/airbyte/server/helpers/ConnectionHelpers.java
@@ -54,6 +54,8 @@ public class ConnectionHelpers {
   private static final String STREAM_NAME_BASE = "users-data";
   private static final String STREAM_NAME = STREAM_NAME_BASE + "0";
   public static final String FIELD_NAME = "id";
+
+  public static final String SECOND_FIELD_NAME = "id2";
   private static final String BASIC_SCHEDULE_TIME_UNIT = "days";
   private static final long BASIC_SCHEDULE_UNITS = 1L;
   private static final String BASIC_SCHEDULE_DATA_TIME_UNITS = "days";
@@ -284,7 +286,7 @@ public static JsonNode generateBasicJsonSchema() {
   public static JsonNode generateJsonSchemaWithTwoFields() {
     return CatalogHelpers.fieldsToJsonSchema(
         Field.of(FIELD_NAME, JsonSchemaType.STRING),
-        Field.of(FIELD_NAME + "2", JsonSchemaType.STRING));
+        Field.of(SECOND_FIELD_NAME, JsonSchemaType.STRING));
   }
 
   public static ConfiguredAirbyteCatalog generateBasicConfiguredAirbyteCatalog() {