diff --git a/index.js b/index.js
index 4680eae..88d44d7 100644
--- a/index.js
+++ b/index.js
@@ -79,12 +79,14 @@ function morgan (format, options) {
   var skip = opts.skip || false
 
   // format function
-  var formatLine = typeof fmt !== 'function'
+  var isFormatFunction = typeof fmt === 'function'
+  var formatLine = !isFormatFunction
     ? getFormatFunction(fmt)
     : fmt
 
   // stream
   var buffer = opts.buffer
+  var isStreamDefined = !!opts.stream
   var stream = opts.stream || process.stdout
 
   // buffering support
@@ -126,8 +128,13 @@ function morgan (format, options) {
         return
       }
 
-      debug('log request')
-      stream.write(line + '\n')
+      if (opts.enableObjectStream && isStreamDefined && isFormatFunction) {
+        debug('log request without newline character')
+        stream.write(line)
+      } else {
+        debug('log request')
+        stream.write(line + '\n')
+      }
     };
 
     if (immediate) {
diff --git a/package.json b/package.json
index 7775fe6..86aa0f1 100644
--- a/package.json
+++ b/package.json
@@ -22,7 +22,7 @@
     "on-headers": "~1.0.1"
   },
   "devDependencies": {
-    "eslint": "5.9.0",
+    "eslint": "5.10.0",
     "eslint-config-standard": "12.0.0",
     "eslint-plugin-import": "2.14.0",
     "eslint-plugin-markdown": "1.0.0-rc.0",
diff --git a/test/morgan.js b/test/morgan.js
index fa5e75a..3f8cfb2 100644
--- a/test/morgan.js
+++ b/test/morgan.js
@@ -1376,6 +1376,77 @@ describe('morgan()', function () {
         .expect(200, done)
     })
   })
+
+  describe('with enableObjectStream option', function () {
+    it('should write an Object to stream based on the custom format function', function (done) {
+      var cb = after(2, function (err, res, streamOutput) {
+        if (err) return done(err)
+        assert(typeof streamOutput === 'object')
+        assert(streamOutput.get === 'GET')
+        done()
+      })
+
+      var customStream = {
+        write: function (streamOutput) {
+          cb(null, null, streamOutput)
+        }
+      }
+
+      var customFormatFunction = function (tokens, req, res) {
+        return { get: tokens.method(req, res) }
+      }
+
+      request(createServer(customFormatFunction, { enableObjectStream: true, stream: customStream }))
+        .get('/fakeEndpoint')
+        .expect(200, cb)
+    })
+
+    it('should write a string to stream when format is not a custom function', function (done) {
+      var cb = after(2, function (err, res, streamOutput) {
+        if (err) return done(err)
+        var masked = streamOutput.replace(/\w+, \d+ \w+ \d+ \d+:\d+:\d+ \w+/, '_timestamp_')
+        assert.strictEqual(masked, res.text + ' - tj [_timestamp_] "GET /fakeEndpoint HTTP/1.1" 200 - "http://localhost/" "my-ua"\n')
+        done()
+      })
+
+      var customStream = {
+        write: function (streamOutput) {
+          cb(null, null, streamOutput)
+        }
+      }
+
+      request(createServer('default', { enableObjectStream: true, stream: customStream }))
+        .get('/fakeEndpoint')
+        .set('Authorization', 'Basic dGo6')
+        .set('Referer', 'http://localhost/')
+        .set('User-Agent', 'my-ua')
+        .expect(200, cb)
+    })
+
+    it('should default to process.stdout when stream is not defined', function (done) {
+      var cb = after(2, function (err, res, line) {
+        if (err) return done(err)
+        assert(res.text.length > 0)
+        assert(typeof line === 'string')
+        done()
+      })
+
+      var stream = createLineStream(function (line) {
+        cb(null, null, line)
+      })
+
+      Object.defineProperty(process, 'stdout', {
+        value: stream
+      })
+
+      var customFormatFunction = function (tokens, req, res) {
+        return { get: tokens.method(req, res) }
+      }
+      request(createServer(customFormatFunction, { enableObjectStream: true, stream: undefined }))
+        .get('/')
+        .expect(200, cb)
+    })
+  })
 })
 
 describe('morgan.compile(format)', function () {