Problem-based learning (PBL) is an established didactic approach in medical education worldwide. The impact of PBL depends on the tutors' quality and the students' motivation. To enhance students' motivation and satisfaction and to overcome the problems with the changing quality of tutors, online learning and face-to-face classes were systematically combined resulting in a blended learning scenario (blended problem-based learning--bPBL). The study aims at determining whether bPBL increases the students' motivation and supports the learning process with respect to the students' cooperation, their orientation, and more reliable tutoring. The blended PBL was developed in a cooperation of students and teachers. The well-established Seven Jump-scheme of PBL was carefully complemented by eLearning modules. On the first training day of bPBL the students start to work together with the online program, but without a tutor, on the final training day the tutor participates in the meeting for additional help and feedback. The program was evaluated by a mixed-method study. The traditional PBL course was compared with the blended PBL by means of qualitative and quantitative questionnaires, standardized group interviews, and students' test results. In addition log-files were analyzed. A total of 185 third-year students and 14 tutors took part in the study. Motivation, subjective learning gains and satisfaction achieved significantly higher ratings by the bPBL students compared with the students learning by traditional PBL. The tutors' opinion and the test results showed no differences between the groups. Working with the web-based learning environment was assessed as very good by the students. According to the log-file analysis, the web-based learning module was frequently used and improved the cooperation during the self-directed learning.