A questionnaire entitled "Attitude toward tobacco usage among health professionals in Puerto Rico" was administered to medical students completing their first and fourth years respectively at the University of Puerto Rico Medical School. Percent of each group currently smoking was found to be 18.5 and 10.8 with an average of 24.2% and 13.5% for 1st and 4th year male students and 9.1% and 3.2% for 1st and 4th year female students. A trend toward beginning smoking at an earlier age was noted as compared to a survey taken 20 years ago. Both groups demonstrated adequate knowledge of the risks and consequences of smoking, however, 4th year students had a wider awareness of smoking hazards. Attitude toward tobacco was highly dependent upon the smoking status of the respondent with non smokers being predictably more strongly opposed to tobacco usage. Although cultural differences exist between Puerto Rican and mainland health professionals, they both share similar knowledge and attitudes toward tobacco usage.