diff --git a/packages/@aws-cdk/core/lib/cfn-parameter.ts b/packages/@aws-cdk/core/lib/cfn-parameter.ts
index 6226f451c2fb8..c9f219d17ae72 100644
--- a/packages/@aws-cdk/core/lib/cfn-parameter.ts
+++ b/packages/@aws-cdk/core/lib/cfn-parameter.ts
@@ -289,8 +289,8 @@ export class CfnParameter extends CfnElement {
    * The parameter value, if it represents a string.
    */
   public get valueAsString(): string {
-    if (!isStringType(this.type)) {
-      throw new Error(`Parameter type (${this.type}) is not a string type`);
+    if (!isStringType(this.type) && !isNumberType(this.type)) {
+      throw new Error(`Parameter type (${this.type}) is not a string or number type`);
     }
     return Token.asString(this.value);
   }
diff --git a/packages/@aws-cdk/core/test/test.cfn-parameter.ts b/packages/@aws-cdk/core/test/test.cfn-parameter.ts
new file mode 100644
index 0000000000000..a370b3948d401
--- /dev/null
+++ b/packages/@aws-cdk/core/test/test.cfn-parameter.ts
@@ -0,0 +1,32 @@
+import { Test } from 'nodeunit';
+import { CfnParameter, Stack } from '../lib';
+
+export = {
+  'valueAsString supports both string and number types'(test: Test) {
+    // GIVEN
+    const stack = new Stack();
+    const numberParam = new CfnParameter(stack, 'numberParam', { type: 'Number', default: 10 });
+    const stringParam = new CfnParameter(stack, 'stringParam', { type: 'String', default: 'a-default' });
+
+    // WHEN
+    const numVal = numberParam.valueAsString;
+    const strVal = stringParam.valueAsString;
+
+    // THEN
+    test.deepEqual(stack.resolve(numVal), { Ref: 'numberParam' });
+    test.deepEqual(stack.resolve(strVal), { Ref: 'stringParam' });
+
+    test.done();
+  },
+
+  'valueAsString fails for unsupported types'(test: Test) {
+    // GIVEN
+    const stack = new Stack();
+    const listParam = new CfnParameter(stack, 'listParam', { type: 'List', default: 10 });
+
+    // WHEN - THEN
+    test.throws(() => listParam.valueAsList, /Parameter type \(List\)/);
+
+    test.done();
+  },
+}
\ No newline at end of file