This paper analyses the effect of being insured under the voluntary component of Vietnamese Health Insurance, on patterns of treatment seeking behaviour. A multinomial logit model is estimated using household survey data from three provinces in Vietnam. Decisions regarding both the type of provider sought and type of care received are analysed. Insurance status is treated as both exogenous and endogenous to account for potential selection bias. The results indicate that, overall, insured patients are more likely to use outpatient facilities, and public providers, an effect that is particularly strong at lower income levels. Copyright © 2004 John Wiley & Sons, Ltd.