Given recent clinical trials establishing the safety and efficacy of adult medical male circumcision (MMC) in Africa, attention has now shifted to barriers and facilitators to programmatic implementation in traditionally non-circumcising communities. In this study, we attempted to develop a fuller understanding of the role of cultural issues in the acceptance of adult circumcision. We conducted four focus-group discussions with 28 participants in Mutoko, Zimbabwe, and 33 participants in Vulindlela, KwaZulu-Natal, South Africa, as well as 19 key informant interviews in both settings. We found the concept of male circumcision to be an alien practice, particularly as expressed in the context of local languages. Cultural barriers included local concepts of ethnicity, social groups, masculinity and sexuality. On the other hand, we found that concerns about the impact of HIV on communities resulted in willingness to consider adult male circumcision as an option if it would result in lowering the local burden of the epidemic. Adult MMC-promotional messages that create a synergy between understandings of both traditional and medical circumcision will be more successful in these communities.