Doctor-patient concordance and patient initiative were examined in a prospective network interview study, with telephone follow-up, of a cohort of 100 patients presenting with low back pain to their family physician. The average overall rate of concordance was 60% (95% CI = 53 to 66), with the highest rates for radiographic imaging studies and sick leave. No correlation was found between concordance and patient parameters. Subjects initiated an average of two (95% CI = 1.7 to 2.3) diagnostic or therapeutic procedures, the most common of which were for medications (40%), followed by bed rest (26%) and back school (22%). One out of every six subjects initiated a referral to a complementary therapist. Positive correlation was found between patient initiatives and pain severity (P = 0.022) and disability (P = 0.02). There was a negative correlation between the subjects' initiatives and their belief that the physician understood the cause of their pain and its influence on their life (P = 0.02). Overall, those patients who described more pain or disability sought more types of diagnostic and therapeutic measures, while those who felt they had been understood sought less.