Adult male circumcision has been shown to reduce the transmission of HIV. Women's acceptability of male circumcision is important in Papua New Guinea's preparedness to introduce male circumcision, and in ethical considerations of its use as a biomedical technology for HIV prevention. We conducted 21 focus group discussions and 18 in-depth interviews with women in all four regions of Papua New Guinea. The majority of women objected to the introduction of male circumcision for three main reasons: circumcision would result in sexual risk compensation; circumcision goes against Christian faith; and circumcision is a new practice that is culturally inappropriate. A minority of women accepted male circumcision for the prevention of HIV and other sexually transmitted infections, and for the benefit of penile hygiene and health. Women's objections to circumcision as a biomedical method of preventing HIV reemphasize the importance of sociocultural and behavioral interventions in Papua New Guinea.