diff --git a/package-lock.json b/package-lock.json
index d916752..ae1633b 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "@apiture/openapi-down-convert",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
diff --git a/package.json b/package.json
index 09634fc..f2ef482 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@apiture/openapi-down-convert",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "description": "Tool to down convert OpenAPI 3.1 to OpenAPI 3.0",
   "main": "lib/src/index.js",
   "bin": {
diff --git a/src/converter.ts b/src/converter.ts
index 4bab609..d72013a 100644
--- a/src/converter.ts
+++ b/src/converter.ts
@@ -251,7 +251,7 @@ export class Converter {
     }
   }
   removeUnsupportedSchemaKeywords() {
-    const keywordsToRemove = ['$id', '$schema', 'unevaluatedProperties'];
+    const keywordsToRemove = ['$id', '$schema', 'unevaluatedProperties', 'contentMediaType'];
     const schemaVisitor: SchemaVisitor = (schema: SchemaObject): SchemaObject => {
       keywordsToRemove.forEach((key) => {
         if (schema.hasOwnProperty(key)) {
diff --git a/test/converter.spec.ts b/test/converter.spec.ts
index 1c74e13..8746255 100644
--- a/test/converter.spec.ts
+++ b/test/converter.spec.ts
@@ -355,6 +355,47 @@ describe('resolver test suite', () => {
     done();
   });
 
+  test('Remove contentMediaType keywords', (done) => {
+    const input = {
+      openapi: '3.1.0',
+      components: {
+        schemas: {
+          a: {
+            type: 'object',
+            unevaluatedProperties: false,
+            properties: {
+              b: {
+                type: 'string',
+                contentMediaType: 'application/pdf',
+                maxLength: 5000000
+              },
+            },
+          },
+        },
+      },
+    };
+    const expected = {
+      openapi: '3.0.3',
+      components: {
+        schemas: {
+          a: {
+            type: 'object',
+            properties: {
+              b: {
+                type: 'string',
+                maxLength: 5000000
+              },
+            },
+          },
+        },
+      },
+    };
+    const converter = new Converter(input, { verbose: true });
+    const converted: any = converter.convert();
+    expect(converted).toEqual(expected);
+    done();
+  });
+
 
    test('Remove webhooks object', (done) => {
     const input = {
diff --git a/test/data/openapi.yaml b/test/data/openapi.yaml
index 8a4fd62..e8f77a2 100644
--- a/test/data/openapi.yaml
+++ b/test/data/openapi.yaml
@@ -63,6 +63,12 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/preferences'
+            application/pdf:
+              schema:
+                type: string
+                contentMediaType: application/json
+                contentEncoding: base64
+                maxLength: 5000000
         '400':
           $ref: '#/components/responses/400'
         '401':