diff --git a/src/model/modifier/DraftModifier.js b/src/model/modifier/DraftModifier.js
index 1d7b04114f..65d91e9cf7 100644
--- a/src/model/modifier/DraftModifier.js
+++ b/src/model/modifier/DraftModifier.js
@@ -18,6 +18,7 @@ import type {DraftInlineStyle} from 'DraftInlineStyle';
 import type {DraftRemovalDirection} from 'DraftRemovalDirection';
 import type SelectionState from 'SelectionState';
 import type {Map} from 'immutable';
+import type {BlockDataMergeBehavior} from 'insertFragmentIntoContentState';
 
 const CharacterMetadata = require('CharacterMetadata');
 const ContentStateInlineStyle = require('ContentStateInlineStyle');
@@ -118,6 +119,7 @@ const DraftModifier = {
     contentState: ContentState,
     targetRange: SelectionState,
     fragment: BlockMap,
+    mergeBlockData?: BlockDataMergeBehavior = 'REPLACE_WITH_NEW_DATA',
   ): ContentState {
     const withoutEntities = removeEntitiesAtEdges(contentState, targetRange);
     const withoutText = removeRangeFromContentState(
@@ -129,6 +131,7 @@ const DraftModifier = {
       withoutText,
       withoutText.getSelectionAfter(),
       fragment,
+      mergeBlockData,
     );
   },
 
diff --git a/src/model/transaction/insertFragmentIntoContentState.js b/src/model/transaction/insertFragmentIntoContentState.js
index bc618b2bbe..a96bf05865 100644
--- a/src/model/transaction/insertFragmentIntoContentState.js
+++ b/src/model/transaction/insertFragmentIntoContentState.js
@@ -26,6 +26,10 @@ const randomizeBlockMapKeys = require('randomizeBlockMapKeys');
 
 const {List} = Immutable;
 
+export type BlockDataMergeBehavior =
+  | 'REPLACE_WITH_NEW_DATA'
+  | 'MERGE_OLD_DATA_TO_NEW_DATA';
+
 const updateExistingBlock = (
   contentState: ContentState,
   selectionState: SelectionState,
@@ -33,6 +37,7 @@ const updateExistingBlock = (
   fragmentBlock: BlockNodeRecord,
   targetKey: string,
   targetOffset: number,
+  mergeBlockData?: BlockDataMergeBehavior = 'REPLACE_WITH_NEW_DATA',
 ): ContentState => {
   const targetBlock = blockMap.get(targetKey);
   const text = targetBlock.getText();
@@ -40,6 +45,17 @@ const updateExistingBlock = (
   const finalKey = targetKey;
   const finalOffset = targetOffset + fragmentBlock.getText().length;
 
+  let data = null;
+
+  switch (mergeBlockData) {
+    case 'MERGE_OLD_DATA_TO_NEW_DATA':
+      data = fragmentBlock.getData().merge(targetBlock.getData());
+      break;
+    case 'REPLACE_WITH_NEW_DATA':
+      data = fragmentBlock.getData();
+      break;
+  }
+
   const newBlock = targetBlock.merge({
     text:
       text.slice(0, targetOffset) +
@@ -50,7 +66,7 @@ const updateExistingBlock = (
       fragmentBlock.getCharacterList(),
       targetOffset,
     ),
-    data: fragmentBlock.getData(),
+    data,
   });
 
   return contentState.merge({
@@ -290,6 +306,7 @@ const insertFragmentIntoContentState = (
   contentState: ContentState,
   selectionState: SelectionState,
   fragmentBlockMap: BlockMap,
+  mergeBlockData?: BlockDataMergeBehavior = 'REPLACE_WITH_NEW_DATA',
 ): ContentState => {
   invariant(
     selectionState.isCollapsed(),
@@ -320,6 +337,7 @@ const insertFragmentIntoContentState = (
       fragment.first(),
       targetKey,
       targetOffset,
+      mergeBlockData,
     );
   }