diff --git a/lib/sources/NPMRegistrySource.js b/lib/sources/NPMRegistrySource.js
index b1647e8..41b90dc 100644
--- a/lib/sources/NPMRegistrySource.js
+++ b/lib/sources/NPMRegistrySource.js
@@ -171,6 +171,8 @@ NPMRegistrySource.prototype.toNixAST = function() {
         case "sha1":
             paramExpr.sha1 = this.sha1;
             break;
+        case "sha256":
+            paramExpr.sha256 = this.sha256;
         case "sha512":
             paramExpr.sha512 = this.sha512;
             break;
diff --git a/lib/sources/Source.js b/lib/sources/Source.js
index f20ded1..69a7391 100644
--- a/lib/sources/Source.js
+++ b/lib/sources/Source.js
@@ -108,6 +108,9 @@ Source.prototype.convertIntegrityStringToNixHash = function(integrity) {
         var hash = base64js.toByteArray(integrity.substring(5));
         this.hashType = "sha1";
         this.sha1 = new Buffer(hash).toString('hex');
+    } else if(integrity.substr(0, 7) === "sha256-") {
+        this.hashType = "sha256";
+        this.sha256 = integrity.substring(7);
     } else if(integrity.substr(0, 7) === "sha512-") {
         this.hashType = "sha512";
         this.sha512 = integrity.substring(7);