Introduction: The low academic performance at the university is influenced by multiple factors manifested in the early years of study. Objectives: To determine the factors affecting the low academic performance of medical students during their first year of studies. Design: Observational, longitudinal study. Non-probability sampling was used for assessments. Setting: San Fernando Faculty of Medicine, San Marcos National University, Lima-Peru. Interventions: A questionnaire, physical, psychological and laboratory examinations were applied. Main outcome measures: Factors that influence low academic performance. Results: Forty students (14 females and 26 males), aged between 18 and 30 years, were evaluated; 31 came from state schools (78%) and 9 from private schools (23%). With regards to study habits, 27 (67%) reported reading the subjects of the profession at least once a day, and 13 (33%...