A cross-sectional study evaluated 182 students in the last two years of medical school and 70 residents of a national hospital in Peru on the risk indicators used for reporting results in clinical trials. A questionnaire was used to assess the ability to recognize and calculate risk indicators most widely used in the epidemiological literature. From the participants, 19.4% did not recognize any of the indicators and 81.4% was not able to calculate them. The relative risk reduction was the most recognized indicator (55.2%), followed by the number needed to treat (51.6%), the absolute risk reduction (26.6%), and the hazard ratio (9.5%). In conclusion, medical students in the last two years of school and medical residents do not recognize or are able to calculate properly the risk indicators used in clinical trials.