As part of a prospective study of treatment decision making among people with HIV infection, we explored perceptions of HAART in a cohort who declined a treatment offer. This was a qualitative study in which 26 gay men were interviewed in relation to their views about HAART soon after treatment was recommended by their HIV physician. Fifteen themes were associated with the decision to decline HAART. These were grouped under three broad categories: doubts about personal necessity for HAART, concerns about potential adverse effects of taking HAART and satisfaction with the amount of personal control over the decision. These findings provide new insights into the type of beliefs that might inform people's evaluation of their perceived need for HAART and their concerns about HAART. Initiatives to support informed decisions should take account of these perceptions.