diff --git a/source/import/importer.js b/source/import/importer.js
index bc4c66a..eff74c5 100644
--- a/source/import/importer.js
+++ b/source/import/importer.js
@@ -163,7 +163,7 @@ OV.FileList = class
     {
         for (let importerIndex = 0; importerIndex < this.importers.length; importerIndex++) {
             let importer = this.importers[importerIndex];
-            let extension = file.extension.toLowerCase ();
+            let extension = file.extension;
             let knownFormats = importer.GetKnownFileFormats ();
             if (knownFormats[extension] !== undefined) {
                 return knownFormats[extension];
@@ -176,7 +176,7 @@ OV.FileList = class
     {
         for (let importerIndex = 0; importerIndex < this.importers.length; importerIndex++) {
             let importer = this.importers[importerIndex];
-            if (importer.CanImportExtension (file.extension.toLowerCase ())) {
+            if (importer.CanImportExtension (file.extension)) {
                 return importer;
             }
         }
diff --git a/source/io/fileutils.js b/source/io/fileutils.js
index 176059d..3dec5f2 100644
--- a/source/io/fileutils.js
+++ b/source/io/fileutils.js
@@ -34,7 +34,8 @@ OV.GetFileExtension = function (filePath)
 	if (firstPoint === -1) {
 		return '';
 	}
-	return fileName.substr (firstPoint + 1);
+	let extension = fileName.substr (firstPoint + 1);
+	return extension.toLowerCase ();
 };
 
 OV.RequestUrl = function (url, format)
diff --git a/test/tests/fileutils_test.js b/test/tests/fileutils_test.js
index 7cc5aa0..1ffb4c9 100644
--- a/test/tests/fileutils_test.js
+++ b/test/tests/fileutils_test.js
@@ -13,7 +13,7 @@ describe ('File Utils', function () {
     it ('Get File Extension', function () {
         assert.strictEqual (OV.GetFileExtension ('file'), '');
         assert.strictEqual (OV.GetFileExtension ('file.obj'), 'obj');
-        assert.strictEqual (OV.GetFileExtension ('file.OBJ'), 'OBJ');
+        assert.strictEqual (OV.GetFileExtension ('file.OBJ'), 'obj');
     });    
     
     it ('Get File Name', function () {
diff --git a/website/o3dv/js/website.js b/website/o3dv/js/website.js
index af964c6..a622e41 100644
--- a/website/o3dv/js/website.js
+++ b/website/o3dv/js/website.js
@@ -119,7 +119,7 @@ OV.Website = class
     
     OnModelFinished (importResult, threeMeshes)
     {
-        let importedExtension = OV.GetFileExtension (importResult.mainFile).toLowerCase ();
+        let importedExtension = OV.GetFileExtension (importResult.mainFile);
         this.eventHandler.HandleEvent ('model_loaded', { extension : importedExtension });
         this.model = importResult.model;
         this.ShowViewer (true);