diff --git a/omod-1.9/src/main/java/org/openmrs/module/webservices/rest/web/v1_0/resource/openmrs1_9/CustomDatatypeResource1_9.java b/omod-1.9/src/main/java/org/openmrs/module/webservices/rest/web/v1_0/resource/openmrs1_9/CustomDatatypeResource1_9.java
index 72b40d62a..7762a01b4 100644
--- a/omod-1.9/src/main/java/org/openmrs/module/webservices/rest/web/v1_0/resource/openmrs1_9/CustomDatatypeResource1_9.java
+++ b/omod-1.9/src/main/java/org/openmrs/module/webservices/rest/web/v1_0/resource/openmrs1_9/CustomDatatypeResource1_9.java
@@ -14,6 +14,7 @@
 import io.swagger.models.properties.ArrayProperty;
 import io.swagger.models.properties.RefProperty;
 import io.swagger.models.properties.StringProperty;
+import org.openmrs.api.APIAuthenticationException;
 import org.openmrs.api.context.Context;
 import org.openmrs.customdatatype.CustomDatatype;
 import org.openmrs.customdatatype.CustomDatatypeHandler;
@@ -129,6 +130,9 @@ protected PageableResult doGetAll(RequestContext context) throws ResponseExcepti
 	}
 	
 	private List<CustomDatatypeRepresentation> getAllCustomDatatypes() {
+		if(!Context.isAuthenticated()) {
+			throw new APIAuthenticationException("User must be authenticated!");
+		}
 		List<String> datatypeClassnames = CustomDatatypeUtil.getDatatypeClassnames();
 		
 		List<CustomDatatypeRepresentation> datatypes = new ArrayList<CustomDatatypeRepresentation>();