In this paper, we assess the capacity of Vietnamese commercial banks to withstand the effects of an increase in credit risk as a result of macroeconomic shocks. Firstly, VAR model is used to estimate the relationship among macro variables (real GDP, real exchange rate, lending interest rate and inflation rate) and from that, macroeconomic scenarios are set up. Next, we employ a GMM model to estimate the relationship between the non-performing loan ratio (credit risk) and macro variables involved in first step. Finally, the new capital requirement ratio (CAR) is recalculated, which is based on the increase in loan provision followed by the rise in non-performing loan. The results show that credit risk which the commercial banks have to face is relatively limited when their risk weighted assets are unchanged. If these numbers, however, increase as banks broaden their lending, all banks’ CAR will reduce remarkably and four large banks will be lack of capital seriously and cannot meet the requirement of Central Bank.