Motivations for condom use are intricate and the behaviour of individuals and couples takes place in complex sociocultural settings. This study examines in detail the sociocultural context of condom use among the Maasai, an east African agropastoralist population. A review of the ethno-demographic literature demonstrates the sociocultural significance of semen in a range of settings. A detailed description of Maasai values relating to semen is followed by an analysis presenting results from a sample survey and focus group discussions. Whilst reported knowledge of HIV/AIDS was high (100%), unprompted reporting of condoms as a way of preventing HIV infection was low. When asked directly about knowledge of condoms, awareness appeared high but levels of detailed condom knowledge were very low. Of those individuals who reported that they knew what a condom was, only 17% said that they knew how they worked. Focus group discussions reveal strongly held opinions and beliefs connected to condoms and their use, including their contraceptive effects, negative impact on quality of sex, the wasting of semen and the 'otherness' of condoms. The implications of these findings for condom provision and uptake are considered.