The fact that the majority of northern Vietnamese households are small and contain only two generations is often interpreted as evidence of the effects of socialism on the Vietnamese family. The observed pattern is, however, typical of a stem household system like that of northern Vietnam, and probably predates the Revolution. Virtually all discussions of northern Vietnamese households have concentrated on cross-sectional measures of household size and structure. Such measures must be combined with longitudinal measures and measures of size as experienced by household members to give a full picture of northern Vietnamese households. On all these measures southern Vietnamese households appear significantly different from northern Vietnamese households.