diff --git a/servo/components/script/dom/blob.rs b/servo/components/script/dom/blob.rs
index dc24cbb01fc8..9c23b8f6da06 100644
--- a/servo/components/script/dom/blob.rs
+++ b/servo/components/script/dom/blob.rs
@@ -4,11 +4,14 @@
 
 use dom::bindings::codegen::Bindings::BlobBinding;
 use dom::bindings::codegen::Bindings::BlobBinding::BlobMethods;
+use dom::bindings::codegen::UnionTypes::BlobOrString;
 use dom::bindings::error::Fallible;
 use dom::bindings::global::GlobalRef;
 use dom::bindings::js::Root;
 use dom::bindings::reflector::{Reflectable, Reflector, reflect_dom_object};
 use dom::bindings::trace::JSTraceable;
+use encoding::all::UTF_8;
+use encoding::types::{EncoderTrap, Encoding};
 use num::ToPrimitive;
 use std::ascii::AsciiExt;
 use std::borrow::ToOwned;
@@ -120,16 +123,29 @@ impl Blob {
 
     // https://w3c.github.io/FileAPI/#constructorBlob
     pub fn Constructor_(global: GlobalRef,
-                        blobParts: DOMString,
+                        blobParts: Vec<BlobOrString>,
                         blobPropertyBag: &BlobBinding::BlobPropertyBag)
                         -> Fallible<Root<Blob>> {
-        // TODO: accept other blobParts types - ArrayBuffer or ArrayBufferView or Blob
+
+        // TODO: accept other blobParts types - ArrayBuffer or ArrayBufferView
+        let bytes: Vec<u8> = blobParts.iter()
+                                .flat_map(|bPart| {
+                                    match bPart {
+                                        &BlobOrString::String(ref s) => {
+                                            UTF_8.encode(s, EncoderTrap::Replace).unwrap()
+                                        },
+                                        &BlobOrString::Blob(ref b) => {
+                                            b.get_data().get_bytes().to_vec()
+                                        },
+                                    }
+                                })
+                                .collect();
         let typeString = if is_ascii_printable(&blobPropertyBag.type_) {
             &*blobPropertyBag.type_
         } else {
             ""
         };
-        Ok(Blob::new(global, blobParts.into(), &typeString.to_ascii_lowercase()))
+        Ok(Blob::new(global, bytes, &typeString.to_ascii_lowercase()))
     }
 
     pub fn get_data(&self) -> &DataSlice {
diff --git a/servo/components/script/dom/webidls/Blob.webidl b/servo/components/script/dom/webidls/Blob.webidl
index 5f338a152399..bad890fafdcd 100644
--- a/servo/components/script/dom/webidls/Blob.webidl
+++ b/servo/components/script/dom/webidls/Blob.webidl
@@ -4,11 +4,9 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 // http://dev.w3.org/2006/webapi/FileAPI/#dfn-Blob
-//[Exposed=Window,Worker][Constructor,
-// Constructor(sequence<(ArrayBuffer or ArrayBufferView or Blob or DOMString)> blobParts,
-//             optional BlobPropertyBag options)]
 [Constructor,
- Constructor(DOMString blobParts, optional BlobPropertyBag options),
+ Constructor(sequence<(/*ArrayBuffer or ArrayBufferView or */Blob or DOMString)> blobParts,
+  optional BlobPropertyBag options),
  Exposed=Window/*,Worker*/]
 interface Blob {