Purpose: This study examined the impact of medical education on students' views of substance abuse treatment, public policy options and training. Method: A longitudinal survey was conducted on a single-class cohort of 101 students in a major American, urban medical school. The survey was administered in the Spring semesters of the first to third years of the curriculum. The survey evaluated attitudes in three areas: (1) Treatment: efficacy of treatment and ideal level of physician involvement in substance abuse issues, (2) Public policy: degrees of support for competing public policy strategies and (3) Training: the amount of substance abuse education offered in medical school. Results: Response rates were 92% in the first year, 90% in the second and 75% in the third. About 54% of respondents were female, 55% were white (non-Hispanic) and 71% were 20-24 years old. Treatment: students held consistent views towards treating substance abuse patients, but there was a significant decline in the percentage who felt that drug addiction can be successfully treated (from 47 to 22%, p less than 0.001). Public policy: support for public health approaches ranged from 86 to 92%, but most criminal justice approaches were favoured by fewer than 40% of respondents. Training: respondents reported a significant increase in any degree of substance abuse training (p = 0.0001); classroom and clinical experiences were the predominant sources of training. Conclusions: Surveyed medical students retained many of their a "priori" beliefs about substance abuse, though there were some significant changes during the survey period. Further studies are required to evaluate how these views were established and how medical education impacts potentially malleable attitudes. (Contains 1 table and 6 figures.)