diff --git a/main/src/com/google/refine/exporters/XlsExporter.java b/main/src/com/google/refine/exporters/XlsExporter.java
index 59e005fa4..18458ac37 100644
--- a/main/src/com/google/refine/exporters/XlsExporter.java
+++ b/main/src/com/google/refine/exporters/XlsExporter.java
@@ -65,7 +65,7 @@ public class XlsExporter implements StreamExporter {
     
     @Override
     public String getContentType() {
-        return xml ? "application/xlsx" : "application/xls";
+        return xml ? "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" : "application/vnd.ms-excel";
     }
 
     @Override
diff --git a/main/tests/server/src/com/google/refine/exporters/XlsExporterTests.java b/main/tests/server/src/com/google/refine/exporters/XlsExporterTests.java
index 221ce30a3..1bae65113 100644
--- a/main/tests/server/src/com/google/refine/exporters/XlsExporterTests.java
+++ b/main/tests/server/src/com/google/refine/exporters/XlsExporterTests.java
@@ -106,6 +106,11 @@ public class XlsExporterTests extends RefineTest {
         options = null;
     }
 
+    @Test
+    public void getContentType(){
+        Assert.assertEquals(SUT.getContentType(), "application/vnd.ms-excel");
+    }
+
     @Test
     public void exportSimpleXls(){
         CreateGrid(2, 2);
diff --git a/main/tests/server/src/com/google/refine/exporters/XlsxExporterTests.java b/main/tests/server/src/com/google/refine/exporters/XlsxExporterTests.java
index 23ad37489..0c8c1a6a7 100644
--- a/main/tests/server/src/com/google/refine/exporters/XlsxExporterTests.java
+++ b/main/tests/server/src/com/google/refine/exporters/XlsxExporterTests.java
@@ -110,6 +110,11 @@ public class XlsxExporterTests extends RefineTest {
         options = null;
     }
 
+    @Test
+    public void getContentType(){
+        Assert.assertEquals(SUT.getContentType(), "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
+    }
+
     @Test
     public void exportSimpleXlsx(){
         CreateGrid(2, 2);
diff --git a/main/webapp/modules/core/MOD-INF/controller.js b/main/webapp/modules/core/MOD-INF/controller.js
index 828cac301..40a898bb3 100644
--- a/main/webapp/modules/core/MOD-INF/controller.js
+++ b/main/webapp/modules/core/MOD-INF/controller.js
@@ -291,7 +291,9 @@ function registerImporting() {
   IM.registerMimeType("application/x-excel", "binary/text/xml/xls/xlsx");
   IM.registerMimeType("application/xls", "binary/text/xml/xls/xlsx");
   IM.registerMimeType("application/x-xls", "binary/text/xml/xls/xlsx");
-  
+  IM.registerMimeType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "binary/text/xml/xls/xlsx");
+  IM.registerMimeType("application/vnd.openxmlformats-officedocument.spreadsheetml.template", "binary/text/xml/xls/xlsx");
+
   IM.registerMimeType("application/vnd.oasis.opendocument.spreadsheet","text/xml/ods");
 
   IM.registerMimeType("application/json", "text/json");