Attitudes towards biochemical experiments and their effect on learning were studied by tests and questionnaires given to four cohorts of medical students directly and 2.5 years after the course. A large number of the students considered that the laboratory exercises had been helpful for learning, especially of methods, whereas other teaching modes were thought to be more important for learning theory. Changing from animal material to the students' own blood in an exercise did not influence the attitudes. Students who performed well on the test of knowledge appreciated the learning value of the exercises more than students who did not. It was concluded that biochemical experiments in the medical curriculum are valuable, but efforts should be directed towards development of the students' attitudes and approaches to the exercises.