OBJECTIVE: To assess if the commercialization of infant formulas, baby bottles, bottle nipples, pacifiers and nipple protectors is performed in compliance with the Norma Brasileira de Comercialização de Alimentos para Lactentes e Crianças de Primeira Infância e de Produtos de Puericultura Correlatos (NBCAL – Brazilian Code of Marketing of Infant and Toddlers Food and Childcare-related products). The commercial promotion of these products is prohibited by the Law 11,265. METHOD: Cross-sectional study conducted in 2017 through a census of all pharmacies, supermarkets and department stores that sold products covered by NBCAL in the South Zone of Rio de Janeiro. Health professionals trained at NBCAL used structured electronic form for direct observation of establishments and for interviews with their managers. We created indicators to evaluate commercial practices and performed descriptive analyses. RESULTS: A total of 352 commercial establishments were evaluated: 240 pharmacies, 88 supermarkets and 24 department stores, of which 88% sold products whose promotion is prohibited by NBCAL. Illegal commercial promotions were found in 20.3% of the establishments that sold the products we investigated: 52 pharmacies (21.9%), four supermarkets (7.5%) and seven department stores (33.3%). The most frequent commercial promotion strategies were discounts (13.2%) and special exposures (9.3%). The products with the highest prevalence of infractions of NBCAL were infant formulas (16.0%). We interviewed 309 managers of commercial establishments; 50.8% reported unfamiliarity with the law. More than three-quarters of the managers reported having been visited at the establishments by commercial representatives of companies that produce infant formulas. CONCLUSION: More than a fifth of commercial establishments promoted infant formulas, baby bottles and nipples, although this practice has been banned in Brazil for thirty years. We think it is necessary to train those managers. Government agencies must monitor commercial establishments in order to inhibit strategies of persuasion and induction to sales of these products, ensuring mothers’ autonomy in the decision on the feeding of their children.