In the bid to explain reproductive health outcomes in most developing countries, men have often been seen as the cause of the problem. However, no systematic attempt has been made to examine men's perception of their own social and health needs, including how ideologies of masculinity impact men's social and physical health. This study examines the Igbo context and shows how men understand and interpret masculinity and the consequences of this for social and health behaviours. Data from adolescent and adult Igbo men aged 15–75 were collected using both quantitative survey interviews (n = 1372) and qualitative techniques such as focus-group discussion (n = 20), in-depth interviews (n = 10) and key informant interviews (n = 10) in selected areas of south-eastern Nigeria. We collected data on gender role ideologies and sexuality issues and practices. Our analysis shows that there are social and health costs associated with adherence to masculine ideologies and a strong association between masculine ideologies and men's health, risk-taking and health-seeking behaviours in the study population. We conclude that all sexual and reproductive health programmes should include services that address the specific needs of men and those negative aspects of masculinity that tend to expose men to adverse health outcomes.