diff --git a/test/encode_test_driver.cc b/test/encode_test_driver.cc
index 25e38bb..92849ba 100644
--- a/test/encode_test_driver.cc
+++ b/test/encode_test_driver.cc
@@ -152,17 +152,19 @@
 #if CONFIG_CICP
   if (img1->fmt != img2->fmt || img1->cp != img2->cp || img1->tc != img2->tc ||
       img1->mc != img2->mc || img1->d_w != img2->d_w ||
-      img1->d_h != img2->d_h) {
+      img1->d_h != img2->d_h || img1->monochrome != img2->monochrome) {
 #else
   if (img1->fmt != img2->fmt || img1->cs != img2->cs ||
-      img1->d_w != img2->d_w || img1->d_h != img2->d_h) {
+      img1->d_w != img2->d_w || img1->d_h != img2->d_h ||
+      img1->monochrome != img2->monochrome) {
 #endif
     if (mismatch_row != NULL) *mismatch_row = -1;
     if (mismatch_col != NULL) *mismatch_col = -1;
     return false;
   }
 
-  for (int plane = 0; plane < 3; plane++) {
+  const int num_planes = img1->monochrome ? 1 : 3;
+  for (int plane = 0; plane < num_planes; plane++) {
     if (!compare_plane(img1->planes[plane], img1->stride[plane],
                        img2->planes[plane], img2->stride[plane],
                        aom_img_plane_width(img1, plane),
diff --git a/test/monochrome_test.cc b/test/monochrome_test.cc
new file mode 100644
index 0000000..f9b9681
--- /dev/null
+++ b/test/monochrome_test.cc
@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2016, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+*/
+
+#include <climits>
+#include <vector>
+#include "third_party/googletest/src/googletest/include/gtest/gtest.h"
+#include "test/codec_factory.h"
+#include "test/encode_test_driver.h"
+#include "test/i420_video_source.h"
+#include "test/video_source.h"
+#include "test/util.h"
+
+namespace {
+
+class MonochromeTest
+    : public ::libaom_test::CodecTestWithParam<libaom_test::TestMode>,
+      public ::libaom_test::EncoderTest {
+ protected:
+  MonochromeTest() : EncoderTest(GET_PARAM(0)), frame0_psnr_y_(0.) {}
+
+  virtual ~MonochromeTest() {}
+
+  virtual void SetUp() {
+    InitializeConfig();
+    SetMode(GET_PARAM(1));
+  }
+
+  virtual void DecompressedFrameHook(const aom_image_t &img,
+                                     aom_codec_pts_t pts) {
+    (void)pts;
+
+    // Get value of top-left corner pixel of U plane
+    int chroma_value = img.planes[AOM_PLANE_U][0];
+
+    bool is_chroma_constant =
+        ComparePlaneToValue(img, AOM_PLANE_U, chroma_value) &&
+        ComparePlaneToValue(img, AOM_PLANE_V, chroma_value);
+
+    // Chroma planes should be constant
+    EXPECT_TRUE(is_chroma_constant);
+
+    // Monochrome flag on image should be set
+    EXPECT_EQ(img.monochrome, 1);
+
+    chroma_value_list_.push_back(chroma_value);
+  }
+
+  // Returns true if all pixels on the plane are equal to value, and returns
+  // false otherwise.
+  bool ComparePlaneToValue(const aom_image_t &img, const int plane,
+                           const int value) {
+    const int w = aom_img_plane_width(&img, plane);
+    const int h = aom_img_plane_height(&img, plane);
+    const uint8_t *const buf = img.planes[plane];
+    const int stride = img.stride[plane];
+
+    for (int r = 0; r < h; ++r) {
+      for (int c = 0; c < w; ++c) {
+        if (buf[r * stride + c] != value) return false;
+      }
+    }
+    return true;
+  }
+
+  virtual void PSNRPktHook(const aom_codec_cx_pkt_t *pkt) {
+    // Check that the initial Y PSNR value is 'high enough', and check that
+    // subsequent Y PSNR values are 'close' to this initial value.
+    if (frame0_psnr_y_ == 0.) {
+      frame0_psnr_y_ = pkt->data.psnr.psnr[1];
+      EXPECT_GT(frame0_psnr_y_, 29.);
+    }
+    EXPECT_NEAR(pkt->data.psnr.psnr[1], frame0_psnr_y_, 2.5);
+  }
+
+  std::vector<int> chroma_value_list_;
+  double frame0_psnr_y_;
+};
+
+TEST_P(MonochromeTest, TestMonochromeEncoding) {
+  ::libaom_test::I420VideoSource video("hantro_collage_w352h288.yuv", 352, 288,
+                                       30, 1, 0, 5);
+
+  init_flags_ = AOM_CODEC_USE_PSNR;
+
+  cfg_.g_w = 352;
+  cfg_.g_h = 288;
+
+  cfg_.rc_buf_initial_sz = 500;
+  cfg_.rc_buf_optimal_sz = 600;
+  cfg_.rc_buf_sz = 1000;
+  cfg_.rc_min_quantizer = 2;
+  cfg_.rc_max_quantizer = 56;
+  cfg_.rc_undershoot_pct = 50;
+  cfg_.rc_overshoot_pct = 50;
+  cfg_.rc_end_usage = AOM_CBR;
+  cfg_.kf_mode = AOM_KF_AUTO;
+  cfg_.g_lag_in_frames = 1;
+  cfg_.kf_min_dist = cfg_.kf_max_dist = 3000;
+  // Enable dropped frames.
+  cfg_.rc_dropframe_thresh = 1;
+  // Disable error_resilience mode.
+  cfg_.g_error_resilient = 0;
+  // Run at low bitrate.
+  cfg_.rc_target_bitrate = 40;
+  // Set monochrome encoding flag
+  cfg_.monochrome = 1;
+
+  ASSERT_NO_FATAL_FAILURE(RunLoop(&video));
+
+  // Check that the chroma planes are equal across all frames
+  std::vector<int>::const_iterator iter = chroma_value_list_.begin();
+  int initial_chroma_value = *iter;
+  for (; iter != chroma_value_list_.end(); ++iter) {
+    // Check that all decoded frames have the same constant chroma planes.
+    EXPECT_EQ(*iter, initial_chroma_value);
+  }
+}
+
+AV1_INSTANTIATE_TEST_CASE(MonochromeTest,
+                          ::testing::Values(::libaom_test::kTwoPassGood));
+
+}  // namespace
diff --git a/test/test.cmake b/test/test.cmake
index 281928c..f670513 100644
--- a/test/test.cmake
+++ b/test/test.cmake
@@ -101,6 +101,12 @@
     "${AOM_ROOT}/test/y4m_video_source.h"
     "${AOM_ROOT}/test/yuv_video_source.h")
 
+if (CONFIG_MONO_VIDEO)
+  set(AOM_UNIT_TEST_ENCODER_SOURCES
+      ${AOM_UNIT_TEST_ENCODER_SOURCES}
+      "${AOM_ROOT}/test/monochrome_test.cc")
+endif ()
+
 if (NOT BUILD_SHARED_LIBS)
   set(AOM_UNIT_TEST_ENCODER_SOURCES
       ${AOM_UNIT_TEST_ENCODER_SOURCES}