diff --git a/src/plugins/github/demoData/example-github.json b/src/plugins/github/demoData/example-github.json
index 5afb6cb..183c0c9 100644
--- a/src/plugins/github/demoData/example-github.json
+++ b/src/plugins/github/demoData/example-github.json
@@ -286,6 +286,9 @@
                         }
                     },
                     "id": "MDExOlB1bGxSZXF1ZXN0MTcxODg3NzQx",
+                    "mergeCommit": {
+                        "oid": "0a223346b4e6dec0127b1e6aa892c4ee0424b66a"
+                    },
                     "number": 3,
                     "reviews": {
                         "nodes": [
@@ -315,6 +318,9 @@
                         }
                     },
                     "id": "MDExOlB1bGxSZXF1ZXN0MTcxODg4NTIy",
+                    "mergeCommit": {
+                        "oid": "6d5b3aa31ebb68a06ceb46bbd6cf49b6ccd6f5e6"
+                    },
                     "number": 5,
                     "reviews": {
                         "nodes": [
@@ -395,6 +401,7 @@
                         }
                     },
                     "id": "MDExOlB1bGxSZXF1ZXN0MTg1ODA2MTU3",
+                    "mergeCommit": null,
                     "number": 9,
                     "reviews": {
                         "nodes": [
diff --git a/src/plugins/github/graphql.js b/src/plugins/github/graphql.js
index 820656b..29e8e68 100644
--- a/src/plugins/github/graphql.js
+++ b/src/plugins/github/graphql.js
@@ -690,6 +690,8 @@ export type PullRequestJSON = {|
   +author: AuthorJSON,
   +comments: ConnectionJSON<CommentJSON>,
   +reviews: ConnectionJSON<PullRequestReviewJSON>,
+  // If present, oid is the commit SHA of the merged commit.
+  +mergeCommit: ?{|+oid: string|},
 |};
 function pullRequestsFragment(): FragmentDefinition {
   const b = build;
@@ -701,6 +703,7 @@ function pullRequestsFragment(): FragmentDefinition {
       b.field("title"),
       b.field("body"),
       b.field("number"),
+      b.field("mergeCommit", {}, [b.field("oid")]),
       makeAuthor(),
       b.field("comments", {first: b.literal(PAGE_SIZE_COMMENTS)}, [
         b.fragmentSpread("comments"),