This article develops an index of money market pressure to identify banking crises. We define banking crises as periods in which there is excessive demand for liquidity in the money market. We begin with the theoretical foundation of this new method. With the newly defined crisis episodes, we examine the determinants of banking crises using data complied from 47 countries. We find that slowdown of real GDP, lower real interest rates, extremely high inflation, large fiscal deficits, and over-valued exchange rates tend to precede banking crises. The effects of monetary base growth on the probability of banking crises are negligible.