OBJECTIVE To describe effective teaching behaviours of rural family medicine preceptors. METHODS Descriptive qualitative study using the critical incident technique. METHODS Rural Manitoba community practices affiliated with the University of Manitoba's 8-week family medicine/community medicine rotation (clinical clerkship). METHODS All family medicine preceptors and fourth-year medical students involved in two family medicine rotations from Mar. 11 to June 14, 1991. During the first rotation all 12 students and 21 preceptors participated. During the second rotation 12 of the 13 students and 20 of the 21 preceptors participated. The overall response rate was 97%. METHODS Effective and less effective preceptor teaching behaviours. RESULTS During 120 telephone interviews (48 with the students and 72 with the preceptors) 275 critical teaching incidents were elicited. Over 800 teaching behaviours were identified, and seven main categories describing effective teaching behaviours of preceptors were formed: (a) actively involves the student, providing adequate supervision and appropriate independence, (b) develops and fosters a supportive interpersonal relationship with the student to facilitate learning, (c) emphasizes problem solving and the understanding of general principles, (d) balances clinical and teaching responsibilities, (e) demonstrates clinical and professional competence, (f) uses an organized approach, including goal setting and summation, and (g) provides the student with ongoing feedback, assessments and evaluations. CONCLUSIONS The teaching behaviours described in this study augment and corroborate findings from previous studies on clinical teaching and provide a better understanding of effective teaching behaviours. The findings suggest a curriculum for a faculty-development program for rural family medicine preceptors.