diff --git a/src/darwin/Framework/CHIP/CHIPPersistentStorageDelegateBridge.mm b/src/darwin/Framework/CHIP/CHIPPersistentStorageDelegateBridge.mm
index 6e9bfa699c963a..01ea04fd044046 100644
--- a/src/darwin/Framework/CHIP/CHIPPersistentStorageDelegateBridge.mm
+++ b/src/darwin/Framework/CHIP/CHIPPersistentStorageDelegateBridge.mm
@@ -105,7 +105,7 @@
                 } else {
                     error = CHIP_ERROR_NO_MEMORY;
                 }
-                size = decoded.length();
+                size = static_cast<uint16_t>(decoded.length());
             }
         } else {
             error = CHIP_ERROR_KEY_NOT_FOUND;