We compared effects of tutoring by students and by staff. In four courses in each of two consecutive first years of an undergraduate problem-based law curriculum we examined the achievements and perceptions of tutors of students taught by student and staff tutors. Achievements were measured by the results on the regular end-of-course tests. After the end-of-course tests students' perceptions were obtained by an online questionnaire and by a semi-structured focus group interview. The aim of the focus groups was to gain more in-depth insight into students' perceptions. No significant differences in achievement and perceptions of tutors were found. Students' perceptions of both staff and student tutors were generally positive. The results suggest that students that are carefully selected and well trained can be effective as tutors in the first year of an undergraduate problem-based curriculum. (Contains 5 tables.)