The objective of the study was to evaluate the effect of Minulet, a new low-dose oral contraceptive on mood in two groups and to compare the effect with a control group of women not taking oral contraceptives (OC). The women participating were between 16 and 45 years of age. They completed the Amsterdam Mood Questionnaire (AMQ) and the Sickness Impact Profile (SIP) three times. They were filled in before treatment started, after taking Minulet for one month and then again after three months. The questionnaires were filled in by a group of 200 women who had not taken OC before (starters), and by a second group of 370 women who were already taking OC (switchers). A group of 140 women who did not use any OC during the study served as a control group. These women also filled in the same questionnaires, both at the start, and after one and three months. As far as the AMQ was concerned, the switchers appeared in the initial measurement to have significantly higher scores (that is to say, a worse mood) for "tiredness", "depression", "moodiness", "anxiety" and "anger", than those of the starters and the control group. Moreover, the switchers had reduced scores (that is to say, an improved mood) on the AMQ-scales during their use of Minulet compared to their initial use of oral contraceptives. The scores of the starters and the control group on the AMQ-scales remained unchanged on all three measurements. It can be concluded from this that these groups felt as well as they did before. With regard to the SIP: in the initial measurement, the switchers appeared to have less favourable scores in the SIP categories "emotional behaviour", "social interaction", and "alertness" than the control group. Also, at baseline the switchers appeared to score less favourably than the starters with regard to "social interactions" only. The switchers scored more favourably on all mentioned SIP categories during their use of Minulet than at baseline. The starters and the control group continued to feel the same on all three measurements for the SIP. The results of the SIP were in accordance with the results of the AMQ. Based on this study, it was concluded that women who had not been taking OC and who started taking Minulet, continued to feel the same as they did before. Secondly, it was concluded that women who switched over from their usual OC to Minulet felt that their mood improved. © 1992.