We examine the acceptance of sexual relations outside marriage and levels of marital sexual activity using data on married individuals from Hai Duong province collected in 2001. There is a growing acceptance of intimate behavior without marital commitment and sex with a future spouse in urban areas among individuals who married after the renovation in the late 1980's. Schooling, urban residence and marrying after the renovation have stronger associations with less conservative attitudes for men than women. Even among younger and better-educated individuals, acceptance of premarital and extramarital sex remains below the majority. Premarital sex is more common among men than women, and reported levels are far lower than in other parts of Asia, or Africa and Latin America. The reported level of sexual activity within marriage is similar to that observed in other countries. The incidence of sex declines with age and men are more likely to report sex with their spouse than women at all ages. We consider the methodological implications of these gender differences in sexual activity.