Aims: To determine whether preclinical medical students are able to learn therapeutic problem solving simultaneously with gaining knowledge of pharmacology. Methods: A randomized controlled pre/post-test study among 85 3rd year preclinical medical students from two medical faculties in Amsterdam. In addition to the normal curriculum, the study group followed a course, which was a copy of the obligatory training in cognitive therapeutic skills for 5th year students who had gained knowledge first, followed by applying the knowledge. Before, immediately after and 9 months after the training both the study group and a control group took a test (T0, T1, T2). The level of knowledge and cognitive therapeutic skills were assessed. As a reference, 38 5th year students also took the tests. Results: On T0 the levels of cognitive therapeutic skills of the study and control groups were similar (26.7% and 27.4% of the required level for graduation, respectively). On T1 and T2, the study group scored significantly higher compared with the control group: 46.0/36.7% and 41.3/36.3%, respectively (P < 0.05). In comparison with T0, the scores of the study group on T1 increased significantly and showed no significant decline on T2. There were no differences between the groups with respect to the level of knowledge in any of the three tests. The level of cognitive therapeutic skills in the 5th year reference group increased slightly but not significantly from 40.3% to 44.5% after the training; the level of knowledge increased significantly from 48.8% to 68.0%. Conclusions: Preclinical medical students are able to learn cognitive therapeutic skills simultaneously with gaining knowledge of pharmacology.