Introduction: Physicians and medical students need to understand numerical and graphical health data in order to provide patients with correct information. Objective: The graphical and numerical skills of medical students and residents from a private university in Lima, Peru, were determined in this investigation. Method: Cross-sectional, descriptive study. The Objective Numeracy, Subjective Numeracy and Graph Literacy Scales were applied to medical students at their two final years of medical school and to medical residents. Results: Of 169 participants, 52.07% were sixth-year and 18.34% were seventh-year students and 29.58% were residents. Mean objective numeracy score was 7.34, mean subjective numeracy was 34.12 and mean graph literacy was 10.35. A multiple linear regression analysis showed that Subjective and Objective Numeracy Scales highest means were associated with the male gender and training on research methodology (p < 0.05). Graph Literacy Scale highest means were associated with the male gender and younger age (p-value < 0.05). Conclusion: Numeracy and Graph Literacy Scales mean scores were high in medical students.