To evaluate the pattern of breastfeeding and weaning as a risk of obesity in pre-school children from a Primary Care Unit. Cross-sectional analytical study LOCATION: Cancun, Quintana Roo (Mexico). Children from 2-4 years of age from a Primary Care Unit. Duration of total and exclusive breastfeeding, age and food utilized for complementary feeding reported by the mother or career of the child and nutritional status assessment evaluated by body mass index (BMI) ≥ 95 percentile. Determination of prevalence ratio (PR), odds ratio (OR), chi squared (x2), and binary logistic regression. The study included 116 children (55.2% girls) with a mean age of 3.2 years, with obesity present in 62.1%, Exclusive breastfeeding in 72.4% with mean duration of 2.3 months, and age at introducing solids foods was 5.0 months. There was a difference for breastfeeding and complementary feeding by gender sex (P