Introduction. In developed countries, public campaigns promoting recommendations on safe infant sleep increased adherence to the supine sleeping position to more than 70% and, at the same time, reduced the incidence of sudden infant death syndrome by 53%. Objective. To determine the impact, at 60 days of life, of an educational intervention conducted in maternity centers aimed at improving adherence to the recommendations on safe infant sleep. Population, material and methods. Intervention study with historical control conducted between February 1 st and September 30 th of 2014 at the Maternity Center of Hospital Meisner and Hospital Universitario Austral. The intervention was called "crib card" and consisted in training health care team members and providing families with information on safe infant sleep by means of lessons, written material and using stickers on cribs. Results. Five hundred and fifty newborn infants were included. After the intervention, a 35% increase in the supine sleeping position (p < 0.0001) was observed; exclusive breastfeeding increased by 11% (p= 0.01); and co-sleeping decreased from 31% to 18% (p< 0.0005). No differences were observed in relation to bedroom sharing, living with tobacco users, or pacifier use at 60 days of life. Conclusions. The educational intervention was useful to improve adherence to the recommendations on safe sleep at 60 days of life: using the supine position and breastfeeding improved, and the rate of co-sleeping decreased. No changes were observed in the number of household members who smoke, bedroom sharing, and pacifier use.