diff --git a/src/patcher/content-types-manager.spec.ts b/src/patcher/content-types-manager.spec.ts
index 5bcebe8c9d..7e4554cf5b 100644
--- a/src/patcher/content-types-manager.spec.ts
+++ b/src/patcher/content-types-manager.spec.ts
@@ -47,5 +47,31 @@ describe("content-types-manager", () => {
                 type: "element",
             });
         });
+
+        it("should not append duplicate content type", () => {
+            const element = {
+                type: "element",
+                name: "xml",
+                elements: [
+                    {
+                        type: "element",
+                        name: "Types",
+                        elements: [
+                            {
+                                type: "element",
+                                name: "Default",
+                                attributes: {
+                                    ContentType: "image/png",
+                                    Extension: "png",
+                                },
+                            },
+                        ],
+                    },
+                ],
+            };
+            appendContentType(element, "image/png", "png");
+
+            expect(element.elements.length).toBe(1);
+        });
     });
 });
diff --git a/src/patcher/content-types-manager.ts b/src/patcher/content-types-manager.ts
index 8032073bfc..8829c3349b 100644
--- a/src/patcher/content-types-manager.ts
+++ b/src/patcher/content-types-manager.ts
@@ -4,6 +4,18 @@ import { getFirstLevelElements } from "./util";
 
 export const appendContentType = (element: Element, contentType: string, extension: string): void => {
     const relationshipElements = getFirstLevelElements(element, "Types");
+
+    const exist = relationshipElements.some(
+        (el) =>
+            el.type === "element" &&
+            el.name === "Default" &&
+            el?.attributes?.ContentType === contentType &&
+            el?.attributes?.Extension === extension,
+    );
+    if (exist) {
+        return;
+    }
+
     // eslint-disable-next-line functional/immutable-data
     relationshipElements.push({
         attributes: {