['The relationship between physicians and the pharmaceutical industry is controversial because of the potential for conflicts of interest. However, little empirical evidence exists on the extent of physician participation in activities sponsored by pharmaceutical companies.', 'To determine the prevalence of participation of internal medicine physicians in clinical trials and lectures sponsored by pharmaceutical companies and to describe factors that are associated with such participation.', 'We conducted a cross-sectional regional survey of 1,000 Maryland internal medicine physicians between February 2000 and January 2001 in order to measure the prevalence of physician participation in pharmaceutical-sponsored clinical trials and lectures. We also collected economic and demographic information to examine potential associations between physician characteristics and engagement in such activities.', 'Of 835 eligible physicians 444 (53%) responded, of whom 37% reported engaging in pharmaceutical-sponsored clinical trials and/or lectures to supplement their incomes. In our multivariable analysis, subspecialists versus generalist physicians (odds ratio [OR], 1.85; 95% confidence interval [CI], 1.14 to 2.99), physicians in private group-single specialty and academic practice versus physicians in solo practice (OR, 2.30; 95% CI, 1.19 to 4.44 and OR, 2.56; 95% CI, 1.17 to 5.61, respectively), and physicians with higher versus lower annual incomes (OR, 1.22; 95% CI, 1.04 to 1.44) had a greater odds of participation in these activities. Additionally, physicians dissatisfied with their income had a 140% greater odds of participation (OR, 2.36; 95% CI, 1.45 to 3.83) than those who were satisfied with their income.'] Does prevalence and determinants of physician participation in conducting pharmaceutical-sponsored clinical trials and lecture?