diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AbstractCSharpCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AbstractCSharpCodegen.java
index d45153dd521..bbd06e02421 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AbstractCSharpCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AbstractCSharpCodegen.java
@@ -555,6 +555,12 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
     public String getSwaggerType(Property p) {
         String swaggerType = super.getSwaggerType(p);
         String type;
+
+        if (swaggerType == null) {
+            swaggerType = ""; // set swagger type to empty string if null
+        }
+
+        // TODO avoid using toLowerCase as typeMapping should be case-sensitive
         if (typeMapping.containsKey(swaggerType.toLowerCase())) {
             type = typeMapping.get(swaggerType.toLowerCase());
             if (languageSpecificPrimitives.contains(type)) {