diff --git a/doc/api/repositories.md b/doc/api/repositories.md
index 17f388194d2..9ec6ba74125 100644
--- a/doc/api/repositories.md
+++ b/doc/api/repositories.md
@@ -384,3 +384,16 @@ Parameters:
 + `branch_name` (required) - The name of branch
 + `content` (required) - File content
 + `commit_message` (required) - Commit message
+
+## Update existing file in repository
+
+```
+PUT /projects/:id/repository/files
+```
+
+Parameters:
+
++ `file_path` (required) - Full path to file. Ex. lib/class.rb
++ `branch_name` (required) - The name of branch
++ `content` (required) - New file content
++ `commit_message` (required) - Commit message
diff --git a/lib/api/files.rb b/lib/api/files.rb
index 1692d3d3a20..e467b0f8e9a 100644
--- a/lib/api/files.rb
+++ b/lib/api/files.rb
@@ -16,9 +16,10 @@ module API
       #
       # Example Request:
       #   POST /projects/:id/repository/files
+      #
       post ":id/repository/files" do
-        required_attributes! [:file_name, :branch_name, :content]
-        attrs = attributes_for_keys [:file_name, :file_path, :branch_name, :content]
+        required_attributes! [:file_name, :branch_name, :content, :commit_message]
+        attrs = attributes_for_keys [:file_name, :file_path, :branch_name, :content, :commit_message]
         branch_name = attrs.delete(:branch_name)
         file_path = attrs.delete(:file_path)
         result = ::Files::CreateContext.new(user_project, current_user, attrs, branch_name, file_path).execute
@@ -35,6 +36,37 @@ module API
           render_api_error!(result[:error], 400)
         end
       end
+
+      # Update existing file in repository
+      #
+      # Parameters:
+      #   file_name (required) - The name of new file. Ex. class.rb
+      #   file_path (optional) - The path to new file. Ex. lib/
+      #   branch_name (required) - The name of branch
+      #   content (required) - File content
+      #   commit_message (required) - Commit message
+      #
+      # Example Request:
+      #   PUT /projects/:id/repository/files
+      #
+      put ":id/repository/files" do
+        required_attributes! [:file_path, :branch_name, :content, :commit_message]
+        attrs = attributes_for_keys [:file_path, :branch_name, :content, :commit_message]
+        branch_name = attrs.delete(:branch_name)
+        file_path = attrs.delete(:file_path)
+        result = ::Files::UpdateContext.new(user_project, current_user, attrs, branch_name, file_path).execute
+
+        if result[:status] == :success
+          status(200)
+
+          {
+            file_path: file_path,
+            branch_name: branch_name
+          }
+        else
+          render_api_error!(result[:error], 400)
+        end
+      end
     end
   end
 end
diff --git a/spec/requests/api/files_spec.rb b/spec/requests/api/files_spec.rb
index 637680672da..345f2bae65a 100644
--- a/spec/requests/api/files_spec.rb
+++ b/spec/requests/api/files_spec.rb
@@ -10,6 +10,15 @@ describe API::API do
   before { project.team << [user, :developer] }
 
   describe "POST /projects/:id/repository/files" do
+    let(:valid_params) {
+      {
+        file_name: 'newfile.rb',
+        branch_name: 'master',
+        content: 'puts 8',
+        commit_message: 'Added newfile'
+      }
+    }
+
     it "should create a new file in project repo" do
       Gitlab::Satellite::NewFileAction.any_instance.stub(
         commit!: true,
@@ -35,12 +44,38 @@ describe API::API do
     end
   end
 
-  def valid_params
-    {
-      file_name: 'newfile.rb',
-      branch_name: 'master',
-      content: 'puts 8',
-      commit_message: 'Added newfile'
+  describe "PUT /projects/:id/repository/files" do
+    let(:valid_params) {
+      {
+        file_path: 'spec/spec_helper.rb',
+        branch_name: 'master',
+        content: 'puts 8',
+        commit_message: 'Changed file'
+      }
     }
+
+    it "should update existing file in project repo" do
+      Gitlab::Satellite::EditFileAction.any_instance.stub(
+        commit!: true,
+      )
+
+      put api("/projects/#{project.id}/repository/files", user), valid_params
+      response.status.should == 200
+      json_response['file_path'].should == 'spec/spec_helper.rb'
+    end
+
+    it "should return a 400 bad request if no params given" do
+      put api("/projects/#{project.id}/repository/files", user)
+      response.status.should == 400
+    end
+
+    it "should return a 400 if satellite fails to create file" do
+      Gitlab::Satellite::EditFileAction.any_instance.stub(
+        commit!: false,
+      )
+
+      put api("/projects/#{project.id}/repository/files", user), valid_params
+      response.status.should == 400
+    end
   end
 end