A 3-year follow-up evaluation was conducted of an experimental problem-based learning (PBL) integrated curriculum directed to students of the first 2 years of engineering. The PBL curriculum brought together the contents of physics, mathematics, and computer science courses in a single course in which students worked on real-life problems. In order to assess academic achievement, three data sources were used: pretest and posttest scores on physics tests for two samples of students, grade point average of all students enrolled in the curriculum, and students' grades in advanced engineering courses in comparison with the grades of students in the traditional courses. A second source of data came from studies that evaluated the acquisition of professional skills. Test scores on critical thinking skills, as well as self-evaluation and co-evaluation tests were used. The final set of data attempted to assess how the PBL curriculum affected students' attitudes toward mathematics, physics, computer science, and education in general. The PBL curriculum seemed to improve the academic achievements of these students, but student attitudes were very similar to those of students in the traditional courses in spite of their enhanced academic achievement. Additional studies are planned to investigate students attitudes toward the PBL course and continued academic achievement. (Contains 12 figures, 3 tables, and 31 references.) (SLD)