In this paper we analyse the effects of microfinance programs upon household welfare in Vietnam. Our analytical framework builds upon the rural household models of Singh et al. (1986) and Rosenzweig (1990). Data on 470 households across 25 villages was collected using a quasiexperiment survey approach to overcome self-selection bias. In our econometric analysis the welfare effects of microfinance are proxied using measures of household income and consumption. The empirical results indicate that participation in microfinance has a positive effect upon household welfare, with the size of the effect increasing at a decreasing rate as a household spends more time in the microfinance program.