diff --git a/usb/device/targets/TARGET_STM/USBPhy_STM32.cpp b/usb/device/targets/TARGET_STM/USBPhy_STM32.cpp
index 472b2021f5..e8ab482f75 100644
--- a/usb/device/targets/TARGET_STM/USBPhy_STM32.cpp
+++ b/usb/device/targets/TARGET_STM/USBPhy_STM32.cpp
@@ -473,7 +473,7 @@ void USBPhyHw::endpoint_abort(usb_ep_t endpoint)
     // TODO - stop the current transfer on this endpoint and don't call the IN or OUT callback
 		HAL_StatusTypeDef ret;
 		ret = HAL_PCD_EP_Abort(&hpcd, endpoint);
-		MBED_ASSERT(ret!=HAL_OK);
+		MBED_ASSERT(ret==HAL_OK);
 		return;
 }