This study used a qualitative interview methodology to explore the barriers to scaling up access to antiretroviral therapy (ART) in Papua New Guinea (PNG). Key informants were selected purposively from organizations active in HIV/AIDS (human immunodeficiency virus/acquired immune deficiency syndrome) work throughout PNG. Interviews were taped, transcribed and analyzed thematically. Predicted barriers likely to impede the delivery of ART by the health services included shortages of skilled and experienced personnel; lack of sustainable funding; weak services at the rural periphery; lack of capacity for the management of chronic illness; inadequacies of basic services for people living with HIV/AIDS (PLWHAs); the difficulty of finding the most appropriate method and venue of delivery for ART; and the complexities of establishing social criteria for deciding who to treat. Barriers likely to impede the acceptance of treatment by the community included the cost of treatment to the patient; the low socioeconomic status of PLWHAs; the effects of stigma, particularly in the case of women; and sociocultural factors affecting public perceptions of ART. The study concluded that, given the range of potential barriers, scaling up ART in PNG and other developing countries will be a complex process, requiring careful decisions to be made over how best to utilize available resources.