diff --git a/src/sharp.cc b/src/sharp.cc
index f0950c01..e461dbc4 100755
--- a/src/sharp.cc
+++ b/src/sharp.cc
@@ -161,6 +161,19 @@ sharp_calc_crop(int const inWidth, int const inHeight, int const outWidth, int c
   return std::make_tuple(left, top);
 }
 
+/*
+  Does this image have an alpha channel?
+  Uses colourspace interpretation with number of channels to guess this.
+*/
+static bool
+sharp_image_has_alpha(VipsImage *image) {
+  return (
+    (image->Bands == 2 && image->Type == VIPS_INTERPRETATION_B_W) ||
+    (image->Bands == 4 && image->Type != VIPS_INTERPRETATION_CMYK) ||
+    (image->Bands == 5 && image->Type == VIPS_INTERPRETATION_CMYK)
+  );
+}
+
 /*
   Initialise a VipsImage from a buffer. Supports JPEG, PNG and WebP.
   Returns the ImageType detected, if any.
@@ -228,6 +241,7 @@ struct metadata_baton {
   int height;
   std::string space;
   int channels;
+  bool has_alpha;
   int orientation;
   std::string err;
 
@@ -276,6 +290,7 @@ class MetadataWorker : public NanAsyncWorker {
       baton->height = image->Ysize;
       baton->space = vips_enum_nick(VIPS_TYPE_INTERPRETATION, image->Type);
       baton->channels = image->Bands;
+      baton->has_alpha = sharp_image_has_alpha(image);
       // EXIF Orientation
       const char *exif;
       if (!vips_image_get_string(image, "exif-ifd0-Orientation", &exif)) {
@@ -303,6 +318,7 @@ class MetadataWorker : public NanAsyncWorker {
       info->Set(NanNew<String>("height"), NanNew<Number>(baton->height));
       info->Set(NanNew<String>("space"), NanNew<String>(baton->space));
       info->Set(NanNew<String>("channels"), NanNew<Number>(baton->channels));
+      info->Set(NanNew<String>("hasAlpha"), NanNew<Boolean>(baton->has_alpha));
       if (baton->orientation > 0) {
         info->Set(NanNew<String>("orientation"), NanNew<Number>(baton->orientation));
       }
diff --git a/tests/fixtures/blackbug.png b/tests/fixtures/blackbug.png
new file mode 100644
index 00000000..f080d05b
Binary files /dev/null and b/tests/fixtures/blackbug.png differ
diff --git a/tests/unit.js b/tests/unit.js
index 4c6123ee..174be885 100755
--- a/tests/unit.js
+++ b/tests/unit.js
@@ -21,6 +21,7 @@ var inputJpgWithExif = path.join(fixturesPath, "Landscape_8.jpg"); // https://gi
 var inputJpgWithGammaHoliness = path.join(fixturesPath, "gamma_dalai_lama_gray.jpg"); // http://www.4p8.com/eric.brasseur/gamma.html
 
 var inputPng = path.join(fixturesPath, "50020484-00001.png"); // http://c.searspartsdirect.com/lis_png/PLDM/50020484-00001.png
+var inputPngWithTransparency = path.join(fixturesPath, "blackbug.png"); // public domain
 var inputWebP = path.join(fixturesPath, "4.webp"); // http://www.gstatic.com/webp/gallery/4.webp
 var inputGif = path.join(fixturesPath, "Crash_test.gif"); // http://upload.wikimedia.org/wikipedia/commons/e/e3/Crash_test.gif
 
@@ -593,6 +594,7 @@ async.series([
       assert.strictEqual(600, metadata.height);
       assert.strictEqual('srgb', metadata.space);
       assert.strictEqual(3, metadata.channels);
+      assert.strictEqual(false, metadata.hasAlpha);
       assert.strictEqual(8, metadata.orientation);
       done();
     });
@@ -606,6 +608,7 @@ async.series([
       assert.strictEqual(3248, metadata.height);
       assert.strictEqual('b-w', metadata.space);
       assert.strictEqual(1, metadata.channels);
+      assert.strictEqual(false, metadata.hasAlpha);
       done();
     });
   },
@@ -618,6 +621,20 @@ async.series([
       assert.strictEqual(2074, metadata.height);
       assert.strictEqual('b-w', metadata.space);
       assert.strictEqual(1, metadata.channels);
+      assert.strictEqual(false, metadata.hasAlpha);
+      done();
+    });
+  },
+  // Metadata - Transparent PNG
+  function(done) {
+    sharp(inputPngWithTransparency).metadata(function(err, metadata) {
+      if (err) throw err;
+      assert.strictEqual('png', metadata.format);
+      assert.strictEqual(2048, metadata.width);
+      assert.strictEqual(1536, metadata.height);
+      assert.strictEqual('srgb', metadata.space);
+      assert.strictEqual(4, metadata.channels);
+      assert.strictEqual(true, metadata.hasAlpha);
       done();
     });
   },
@@ -630,6 +647,7 @@ async.series([
       assert.strictEqual(772, metadata.height);
       assert.strictEqual('srgb', metadata.space);
       assert.strictEqual(3, metadata.channels);
+      assert.strictEqual(false, metadata.hasAlpha);
       done();
     });
   },
@@ -641,6 +659,7 @@ async.series([
       assert.strictEqual(800, metadata.width);
       assert.strictEqual(533, metadata.height);
       assert.strictEqual(3, metadata.channels);
+      assert.strictEqual(false, metadata.hasAlpha);
       done();
     });
   },
@@ -652,6 +671,7 @@ async.series([
       assert.strictEqual(2225, metadata.height);
       assert.strictEqual('srgb', metadata.space);
       assert.strictEqual(3, metadata.channels);
+      assert.strictEqual(false, metadata.hasAlpha);
       done();
     });
   },
@@ -665,6 +685,7 @@ async.series([
       assert.strictEqual(2225, metadata.height);
       assert.strictEqual('srgb', metadata.space);
       assert.strictEqual(3, metadata.channels);
+      assert.strictEqual(false, metadata.hasAlpha);
       done();
     });
     readable.pipe(pipeline);
@@ -679,6 +700,7 @@ async.series([
       assert.strictEqual(2225, metadata.height);
       assert.strictEqual('srgb', metadata.space);
       assert.strictEqual(3, metadata.channels);
+      assert.strictEqual(false, metadata.hasAlpha);
       image.resize(metadata.width / 2).toBuffer(function(err, data, info) {
         if (err) throw err;
         assert.strictEqual(true, data.length > 0);