Background: Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer-related death in females in Mexico as in other Western countries. The most widely used model for breast cancer risk assessment is the Gail Model, which is currently the most validated tool. However, considering it was mainly made for Western populations, its validation in an international context is required. The validation of the Gail Model has never been done for a Latin American country. Methods: In 2002 a cohort of 1000 female patients were recruited at the National Institute of Medical Sciences and Nutrition “Salvador Zubirán”, a tertiary referral center in Mexico City. An assessment of individual breast cancer risk was performed for these patients. At that time, the mean calculated absolute risk utilizing the Gail Model at five years was 1.18%. These patients were followed for 10 years and those who developed breast cancer were identified retrospectively from the medical charts at the institute. Results: Thirty-three patients were lost to follow up. Twenty-four out of 967 individuals developed invasive breast cancer (2.48%). The mean age of these individuals at the time of cancer diagnosis was 63. By the five-year mark, 12 of these patients had developed invasive breast cancer, exactly the same as the predicted Gail Model risk calculated in 2002. Conclusions: Despite the limitation of a small sample, our results suggest that the Gail Model is a well-suited model for breast cancer risk assessment for a Mexican population.