A 6-month longitudinal study of psychological variables predictive of condom use and safer sex in homosexually active men was carried out in Adelaide, a city of one million, in a low prevalence area for human immunodeficiency virus (HIV) infection. Return rate of follow-up questionnaires was 60%, with no significant differences between the returnes and non-returners on age, sexual behaviour, condom use, or any of the subscales of the instruments used: Adjective Check List (ACL), Profile of Mood States (POMS), General Health Questionnaire (GHQ) and Attitudes toward Condoms scale. Variables associated with increased condom use included personality style particularly a more assertive and forceful style, which may be important in raising the issue of condom use with partners and promoting condom use in sexual encounters. These data confirm the findings of previous cross-sectional research. Those items significantly associated with change in the Attitude toward Condoms scale are from the subscales measuring Protection from Infection, and Availability, suggesting that these attitudes are those most closely associated with increasing condom use. The variables associated with lack of change to safer sex are consistently those of dysphoric mood state and psychological maladjustment, suggesting that such individuals may need psychological support to assist them to make the change to safer sex. These data support the view that personality and psychological adjustment are important predictors of risk reduction for HIV infection in homosexually active men.