diff --git a/lib-es5/utils/index.js b/lib-es5/utils/index.js
index 30e447f7..022db5e2 100644
--- a/lib-es5/utils/index.js
+++ b/lib-es5/utils/index.js
@@ -320,7 +320,32 @@ function process_layer(layer) {
   return result;
 }
 
+/**
+ * Parse radius options
+ * @private
+ * @param {Array<string|number>|string|number} radius The radius to parse
+ * @return {string} radius transformation string
+ */
+function process_radius(radius) {
+  if (!radius) {
+    return radius;
+  }
+  if (!isArray(radius)) {
+    radius = [radius];
+  }
+  if (radius.length === 0 || radius.length > 4) {
+    throw new Error("Radius array should contain between 1 and 4 values");
+  }
+  if (radius.findIndex(function (x) {
+    return x === null;
+  }) >= 0) {
+    throw new Error("Corner: Cannot be null");
+  }
+  return radius.map(normalize_expression).join(':');
+}
+
 function base64EncodeURL(sourceUrl) {
+  var ignore;
   try {
     sourceUrl = decodeURI(sourceUrl);
   } catch (error) {
@@ -554,6 +579,7 @@ function generate_transformation_string(options) {
     options.end_offset = _split_range2[1];
   }
   var overlay = process_layer(utils.option_consume(options, "overlay"));
+  var radius = process_radius(utils.option_consume(options, "radius"));
   var underlay = process_layer(utils.option_consume(options, "underlay"));
   var ifValue = process_if(utils.option_consume(options, "if"));
   var custom_function = process_custom_function(utils.option_consume(options, "custom_function"));
@@ -579,7 +605,7 @@ function generate_transformation_string(options) {
     l: overlay,
     o: normalize_expression(utils.option_consume(options, "opacity")),
     q: normalize_expression(utils.option_consume(options, "quality")),
-    r: normalize_expression(utils.option_consume(options, "radius")),
+    r: radius,
     t: named_transformation,
     u: underlay,
     w: normalize_expression(width),
diff --git a/lib/utils/index.js b/lib/utils/index.js
index 9404a6d3..ef55e07b 100644
--- a/lib/utils/index.js
+++ b/lib/utils/index.js
@@ -312,6 +312,28 @@ function process_layer(layer) {
   return result;
 }
 
+/**
+ * Parse radius options
+ * @private
+ * @param {Array<string|number>|string|number} radius The radius to parse
+ * @return {string} radius transformation string
+ */
+function process_radius(radius) {
+  if (!radius) {
+    return radius;
+  }
+  if (!isArray(radius)) {
+    radius = [radius];
+  }
+  if (radius.length === 0 || radius.length > 4) {
+    throw new Error("Radius array should contain between 1 and 4 values");
+  }
+  if (radius.findIndex(x => x === null) >= 0) {
+    throw new Error("Corner: Cannot be null");
+  }
+  return radius.map(normalize_expression).join(':');
+}
+
 function base64EncodeURL(sourceUrl) {
   try {
     sourceUrl = decodeURI(sourceUrl);
@@ -550,6 +572,7 @@ function generate_transformation_string(options) {
     [options.start_offset, options.end_offset] = split_range(utils.option_consume(options, "offset"));
   }
   let overlay = process_layer(utils.option_consume(options, "overlay"));
+  let radius = process_radius(utils.option_consume(options, "radius"));
   let underlay = process_layer(utils.option_consume(options, "underlay"));
   let ifValue = process_if(utils.option_consume(options, "if"));
   let custom_function = process_custom_function(utils.option_consume(options, "custom_function"));
@@ -575,7 +598,7 @@ function generate_transformation_string(options) {
     l: overlay,
     o: normalize_expression(utils.option_consume(options, "opacity")),
     q: normalize_expression(utils.option_consume(options, "quality")),
-    r: normalize_expression(utils.option_consume(options, "radius")),
+    r: radius,
     t: named_transformation,
     u: underlay,
     w: normalize_expression(width),
diff --git a/test/cloudinary_spec.js b/test/cloudinary_spec.js
index 8d6f0937..8449d518 100644
--- a/test/cloudinary_spec.js
+++ b/test/cloudinary_spec.js
@@ -180,7 +180,44 @@ describe("cloudinary", function () {
       }), `${upload_path}/g_center,p_a,q_auto:good,r_3,x_1,y_2/test`);
     });
   });
-  it("should support named transformation", function () {
+  describe(":radius", function() {
+    const upload_path = 'http://res.cloudinary.com/test123/image/upload';
+    it("should support a single value", function() {
+      expect(cloudinary.utils.url("test", {
+        radius: 10
+      })).to.eql(`${upload_path}/r_10/test`);
+      expect(cloudinary.utils.url("test", {
+        radius: '10'
+      })).to.eql(`${upload_path}/r_10/test`);
+      expect(cloudinary.utils.url("test", {
+        variables: [['$v', 10]],
+        radius: '$v',
+      })).to.eql(`${upload_path}/$v_10,r_$v/test`);
+    });
+    it("should support an array of values", function() {
+      expect(cloudinary.utils.url("test", {
+        radius: [10,20,30]
+      })).to.eql(`${upload_path}/r_10:20:30/test`);
+      expect(cloudinary.utils.url("test", {
+        variables: [['$v', 10]],
+        radius: [10,20,'$v'],
+      })).to.eql(`${upload_path}/$v_10,r_10:20:$v/test`);
+      expect(cloudinary.utils.url("test", {
+        variables: [['$v', 10]],
+        radius: [10,20,'$v',40],
+      })).to.eql(`${upload_path}/$v_10,r_10:20:$v:40/test`);
+    })
+    it("should support colon separated values", function() {
+      expect(cloudinary.utils.url("test", {
+        radius: "10:20"
+      })).to.eql(`${upload_path}/r_10:20/test`);
+      expect(cloudinary.utils.url("test", {
+        variables: [['$v', 10]],
+        radius: "10:20:$v:40"
+      })).to.eql(`${upload_path}/$v_10,r_10:20:$v:40/test`);
+    })
+  })
+  it("should support named transformation", function() {
     var options, result;
     options = {
       transformation: "blip",
diff --git a/test/utils_spec.js b/test/utils_spec.js
index 3e517fbb..f0a6690e 100644
--- a/test/utils_spec.js
+++ b/test/utils_spec.js
@@ -343,6 +343,25 @@ describe("utils", function () {
         angle: 'auto',
       }, `http://res.cloudinary.com/${cloud_name}/image/upload/a_auto,c_scale,h_100,w_100/test`, {});
     });
+    it("should disallow radius arrays that contain 0 or more than 4 values", function () {
+      expect(function () {
+        return utils.url("test", {
+          radius: [10, 20, 30, 10, 20]
+        });
+      }).to.throwError(/Radius array should contain between 1 and 4 values/);
+      expect(function () {
+        return utils.url("test", {
+          radius: []
+        });
+      }).to.throwError(/Radius array should contain between 1 and 4 values/);
+    });
+    it("should disallow radius arrays containing null values", function () {
+      expect(function () {
+        return utils.url("test", {
+          radius: [null, 20, 30, 10]
+        });
+      }).to.throwError(/Corner: Cannot be null/);
+    });
     it("should use x, y, radius, prefix, gravity and quality from options", function () {
       test_cloudinary_url("test", {
         x: 1,
@@ -1520,3 +1539,4 @@ describe("utils", function () {
     });
   });
 });
+