Increasing economic integration in East Asia over the last two decades has been evidenced by consistent growth in intra-regional trade and investment. The purpose of this paper is to examine whether financial integration in addition to economic integration has occurring in East Asia and if so, what the extent of financial integration is. Greater economic integration in the region, accompanied by financial deregulation and liberalization, has contributed to greater financial integration. This study confirms increasing degree of financial market integration in East Asia by comparing movements of monthly money market rates before and after the Asian financial crisis of 1997-98. Convergence of interest rates across the countries in East Asia is examined by analyzing deviations, correlation coefficients and multivariate co-integration tests of interest rates for the sample period of 1990-2004. Multivariate co-integration test for the pre-crisis period indicates the existence of at least two stochastic trends, implying lower degree of financial integration. On the other hand, multivariate co-integration test for the post-crisis period indicates the existence of one common stochastic trend. This result indicates convergence of interest rates among the countries with non-stationary interest rate series and implies a higher degree of money market integration in the post-crisis period than in the pre-crisis period.