This paper reports the prevalence and socio-demographic determinants of unintended pregnancy amongst young married couples in Nepal. Information was drawn from a sample survey of 997 young women 499 young men, and data from the Nepal Demographic Health Survey 2001 (NDHS). A new definition of unintended pregnancy was developed. Using bivariate and multivariate analyses, the results show that the conventional NDHS definition of unintended pregnancy provides a substantial under–estimate of prevalence. Unintended pregnancy was more likely to be reported by both men and women who were younger, with a higher number of living children, a smaller desired family size, higher exposure to mass media, a higher level of education and low household well-being; there were also some differences between the sexes. The paper recommends that services should focus on helping those groups of couples who were identified in the analysis as being at increased risk of unintended pregnancy