In this study we examine determinants of intended condom use with casual and steady sex partners among drug users. Our aim was to find out whether anticipated regret and psychopathology represent additional factors in explaining condom use behaviour, on top of the constructs defined in traditional psychosocial models of behaviour. A questionnaire measuring intentions, attitude, beliefs, personal norm, subjective norm, descriptive norm, self-efficacy and anticipated regret toward condom use with steady and casual sex partners, and the Symptom Checklist '90 (to measure dimensions of psychopathology) were handed out to 150 Dutch drug users. The results showed that intended condom use with steady sex partners was mainly predicted by self-efficacy, personal norm and anticipated regret (total R2 = 0.41). Lower feelings of hostility and a more positive personal norm, subjective norm and attitude significantly predicted intended condom use with casual sex partners (total R2 = 0.24). The results also showed that intended condom use with steady sex partners seems to result from anticipating possible barriers, whereas condom use with casual sex partners is largely a matter of having safe sex norms. Practical implications of this study for Aids-preventive campaigns are also discussed.