diff --git a/src/directives/ng-file-drop.ts b/src/directives/ng-file-drop.ts
index 485a34a0..a15d0156 100644
--- a/src/directives/ng-file-drop.ts
+++ b/src/directives/ng-file-drop.ts
@@ -68,6 +68,9 @@ export class NgFileDropDirective implements OnChanges, OnInit {
       return;
     }
 
+    if(this.options.allowedExtensions) {
+      this.options.allowedExtensions = this.options.allowedExtensions.map(ext => ext.toLowerCase());
+    }
     this.options = new NgUploaderOptions(this.options);
     this.uploader.setOptions(this.options);
   }
@@ -107,7 +110,7 @@ export class NgFileDropDirective implements OnChanges, OnInit {
     if (this.options.filterExtensions && this.options.allowedExtensions && this.files && this.files.length) {
       this.files = [].filter.call(this.files, (f: File) => {
         let allowedExtensions = this.options.allowedExtensions || [];
-        if (allowedExtensions.indexOf(f.type) !== -1) {
+        if (allowedExtensions.indexOf(f.type.toLowerCase()) !== -1) {
           return true;
         }
 
diff --git a/src/directives/ng-file-select.ts b/src/directives/ng-file-select.ts
index 67d89b05..64af1eaa 100644
--- a/src/directives/ng-file-select.ts
+++ b/src/directives/ng-file-select.ts
@@ -36,7 +36,9 @@ export class NgFileSelectDirective implements OnChanges {
     if (!this.options || !changes) {
       return;
     }
-
+    if(this.options.allowedExtensions) {
+      this.options.allowedExtensions = this.options.allowedExtensions.map(ext => ext.toLowerCase());
+    }
     this.uploader.setOptions(new NgUploaderOptions(this.options));
 
     this.uploader._emitter.subscribe((data: any) => {
@@ -76,7 +78,7 @@ export class NgFileSelectDirective implements OnChanges {
     if (this.options.filterExtensions && this.options.allowedExtensions && this.files && this.files.length) {
       this.files = [].filter.call(this.files, (f: File) => {
         let allowedExtensions = this.options.allowedExtensions || [];
-        if (allowedExtensions.toLowerCase().indexOf(f.type.toLowerCase()) !== -1) {
+        if (allowedExtensions.indexOf(f.type.toLowerCase()) !== -1) {
           return true;
         }