In a new educational scheme introduced in Malta in 1978, university students spend half of the academic year studying and the other half as workers in various departments. During their work phase, students designed and made working models as teaching aids for the study of physiology. The value of these models was assessed on another group of students before they started their physiology course. These students completed a multiple choice questionnaire on three occasions: before and after having seen the models and after they had had them explained. In addition, they completed a questionnaire designed to elicit their views concerning these models. It was found that the models effectively improved knowledge with little staff involvement. The effectiveness of a model as an aid to learning was directly proportional to the degree of its appeal, but inversely proportional to its complexity in terms of stimulating factors. It is suggested that such models could help in teaching, compensating for shortage of staff, and that students' ability to produce teaching models should be wisely exploited.