diff --git a/types/jspdf/index.d.ts b/types/jspdf/index.d.ts
index c3507fc5e5..ce5b58ed36 100644
--- a/types/jspdf/index.d.ts
+++ b/types/jspdf/index.d.ts
@@ -4,13 +4,14 @@
 //                 Kevin Gonnord <https://github.com/lleios>
 //                 Jackie Weng <https://github.com/jemerald>
 //                 Frank Brullo <https://github.com/frankbrullo>
+//                 Leon Montealegre <https://github.com/leonmontealegre>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 declare module 'jspdf' {
     class jsPDF {
         constructor(orientation?:any,
                     unit?:string,
-                    format?:string,
+                    format?:string|Array<Number>,
                     compressPdf?:number);
 
         CapJoinStyles:any;
diff --git a/types/jspdf/jspdf-tests.ts b/types/jspdf/jspdf-tests.ts
index ab6dd3a82a..3b930f8526 100644
--- a/types/jspdf/jspdf-tests.ts
+++ b/types/jspdf/jspdf-tests.ts
@@ -121,6 +121,15 @@ function test_font_metrics_based_line_sizing_split() {
     pdf.save('Test.pdf');
 }
 
+function test_simple_custom_size_document() {
+    var doc = new jsPDF('l', 'px', [500, 200]);
+    doc.text(20, 20, 'Hello world!');
+    doc.text(20, 30, 'This is client-side Javascript, pumping out a PDF.');
+    doc.addPage();
+    doc.text(20, 20, 'Do you like that?');
+    doc.save('Test.pdf');
+}
+
 function test_from_html() {
     var pdf = new jsPDF('p', 'pt', 'letter')
         , source = document.getElementById('#fromHTMLtestdiv')