In recent years, a number of low- and middle-income country governments have introduced health insurance schemes. Yet not a great deal is known about the impact of such policy shifts. Vietnam’s recent health insurance experience including a health insurance scheme for the poor in 2003 and a compulsory scheme that provides health insurance to all children under six years of age combined with Vietnam’s commitment to universal coverage calls for research that examines the impact of health insurance. Taking advantage of Vietnam’s unique policy environment, data from the 2002, 2004 and 2006 waves of the Vietnam Household Living Standard Survey and single-difference and difference-in-differences approaches are used to assess whether access to health insurance – for the poor, for children and for students – impacts on health services utilization and health outcomes in Vietnam. For the poor and for students, results suggest health insurance increased the use of inpatient services but not of outpatient services or health outcomes. For young children, results suggest health insurance increased the use of outpatient services (including the use of preventive health services such as vaccination and check-up) but not of inpatient services.