diff --git a/lib/platform/bitbucket/__snapshots__/index.spec.ts.snap b/lib/platform/bitbucket/__snapshots__/index.spec.ts.snap
index 3d6b461911c5e15b1a3341a2cf6e9f82e40abef9..3793afe6a79511d5dd2d6f6fc6b96f0e5d58ce43 100644
--- a/lib/platform/bitbucket/__snapshots__/index.spec.ts.snap
+++ b/lib/platform/bitbucket/__snapshots__/index.spec.ts.snap
@@ -1401,13 +1401,12 @@ Array [
   Object {
     "body": Object {
       "close_source_branch": true,
-      "message": "auto merged",
     },
     "headers": Object {
       "accept": "application/json",
       "accept-encoding": "gzip, deflate, br",
       "authorization": "Basic YWJjOjEyMw==",
-      "content-length": "52",
+      "content-length": "28",
       "content-type": "application/json",
       "host": "api.bitbucket.org",
       "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
@@ -1435,13 +1434,12 @@ Array [
     "body": Object {
       "close_source_branch": true,
       "merge_strategy": "fast_forward",
-      "message": "auto merged",
     },
     "headers": Object {
       "accept": "application/json",
       "accept-encoding": "gzip, deflate, br",
       "authorization": "Basic YWJjOjEyMw==",
-      "content-length": "84",
+      "content-length": "60",
       "content-type": "application/json",
       "host": "api.bitbucket.org",
       "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
@@ -1469,13 +1467,12 @@ Array [
     "body": Object {
       "close_source_branch": true,
       "merge_strategy": "merge_commit",
-      "message": "auto merged",
     },
     "headers": Object {
       "accept": "application/json",
       "accept-encoding": "gzip, deflate, br",
       "authorization": "Basic YWJjOjEyMw==",
-      "content-length": "84",
+      "content-length": "60",
       "content-type": "application/json",
       "host": "api.bitbucket.org",
       "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
@@ -1502,13 +1499,12 @@ Array [
   Object {
     "body": Object {
       "close_source_branch": true,
-      "message": "auto merged",
     },
     "headers": Object {
       "accept": "application/json",
       "accept-encoding": "gzip, deflate, br",
       "authorization": "Basic YWJjOjEyMw==",
-      "content-length": "52",
+      "content-length": "28",
       "content-type": "application/json",
       "host": "api.bitbucket.org",
       "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
@@ -1536,13 +1532,12 @@ Array [
     "body": Object {
       "close_source_branch": true,
       "merge_strategy": "squash",
-      "message": "auto merged",
     },
     "headers": Object {
       "accept": "application/json",
       "accept-encoding": "gzip, deflate, br",
       "authorization": "Basic YWJjOjEyMw==",
-      "content-length": "78",
+      "content-length": "54",
       "content-type": "application/json",
       "host": "api.bitbucket.org",
       "user-agent": "RenovateBot/0.0.0-semantic-release (https://github.com/renovatebot/renovate)",
diff --git a/lib/platform/bitbucket/types.ts b/lib/platform/bitbucket/types.ts
index 9e3bb0c16788ee83c499d8d7c7cce92bd55224f6..907cc4071ccb91b6c5447e80651dfccb2e725edf 100644
--- a/lib/platform/bitbucket/types.ts
+++ b/lib/platform/bitbucket/types.ts
@@ -2,6 +2,6 @@ export type BitbucketMergeStrategy = 'fast_forward' | 'merge_commit' | 'squash';
 
 export interface MergeRequestBody {
   close_source_branch?: boolean;
-  message: string;
+  message?: string;
   merge_strategy?: BitbucketMergeStrategy;
 }
diff --git a/lib/platform/bitbucket/utils.ts b/lib/platform/bitbucket/utils.ts
index b68e42b63b2ec78d9db8fc96f3964f5838182cad..a77075053bb690563b9c505c04a90c53b5b2453e 100644
--- a/lib/platform/bitbucket/utils.ts
+++ b/lib/platform/bitbucket/utils.ts
@@ -70,7 +70,6 @@ export function mergeBodyTransformer(
 ): MergeRequestBody {
   const body: MergeRequestBody = {
     close_source_branch: true,
-    message: 'auto merged',
   };
 
   // The `auto` strategy will use the strategy configured inside Bitbucket.