Introduction. Patients with obsessive-compulsive disorder (OCD) often have difficulties in everyday decision making. In addition, recent research suggests that patients have reduced performance on the Iowa Gambling Task, a laboratory decision-making task with implicit rules that taps emotional feedback processing. Disadvantageous decision making is accompanied by reduced skin conductance responses (SCRs) generated during task performance. Methods. The current study investigates behavioural and SCR data during the Iowa Gambling Task (IGT) and additionally the Game of Dice Task (GDT), a decision-making task with explicit and stable rules. We examined 14 patients with OCD and 15 comparison subjects performing the two decision-making tasks while recording accompanying SCR. Results. Patients showed difficulties on the Iowa Gambling Task but not the Game of Dice Task. This was also confirmed by the SCR results. In the Iowa Gambling Task differences in SCR patterns for patients and comparison subjects were observed, whereas SCRs during the Game of Dice Task did not differ between groups. Conclusions. Behavioural and SCR data indicate that patients with OCD have difficulties in decisions under implicit but not under explicit risk conditions.