Objective: To determine the relationship between the consumption of a vegetarian diet and colorectal cancer in adults at two hospitals in Lima. Material and methods: Am analytic case-control study, considering exposition as type of diet and colorectal cancer as the effect, was conducted in Lima, including 142 cases and 143 controls. The cases were adults with colorectal cancer, diagnosed by biopsy, while the control group consisted of adults without colorectal cancer treated at the same hospital, at the same time. Participants responded an instrument that was previously reviewed through a pilot study to evaluate comprehension of the items, and then adjustments were made, with the support of experts. Chisquared was calculated in a bivariate analysis, and a logistic regression model was constructed. Results: The median age was 62 years. The participants were predominantly women, and most had a high school education. The bivariate analysis showed that sex (X2 = 13.01; p valueObjetivo: Determinar la relación que existe entre el consumo de la dieta vegetariana y el cáncer colorrectal en adultos de dos hospitales de Lima. Material y métodos: Se realizó un estudio analítico de casos y controles considerando exposición al tipo de dieta y efecto al cáncer colorrectal. Se incluyeron 142 casos y 143 controles. Los casos fueron adultos con cáncer colorrectal diagnosticados mediante biopsia y el control fue el adulto sin cáncer colorrectal, atendidos en el mismo período y hospital. Se aplicó una encuesta previamente revisada por expertos, se efectuó un estudio piloto para evaluar comprensión y se realizaron los ajustes pertinentes. Se calculó chi cuadrado, OR y regresión logística. Resultados: La mediana de edad fue 62 años, predominantemente mujeres, la mayoría con nivel educativo secundario. El análisis bivariado mostró que el sexo (X2=13.01; valor p