Objective: To assess the frequency and factors associated with the use of whole cow’s milk in children under one year old in the city of Fortaleza, Ceara. Methods: Cross-sectional analytical study conducted with 575 mothers of children under one year old living in the city of Fortaleza, Ceara. A semi-structured questionnaire was applied to collect sociodemographic data and information about the reproductive history of mothers, childbirth and the child. Results: The median age of mothers was 26.5 years, and 80.5% (n=463) of them had a household income of 1-5 minimum wages. The majority (83.2%, n=475) attended more than six prenatal consultations, but only 86.2% (n=494) said they had received information on breastfeeding. Among children who received other types of milk, 53.8% (n=191) consumed whole cow’s milk; of these, 31.7% (n=113) reported having received orientation from the pediatrician. Cow’s milk consumption was associated with maternal age (women under 18 years old (p=0.015)), income of less than five minimum wages (p<0.001), low education level (p<0.001), unemployment (p<0.001), reduced number of prenatal consultations (p=0.019), childbirth at public hospital (p<0.001), no breastfeeding before discharge from maternity hospital (p<0.001) and not having a health insurance (p<0.001). Conclusion: There was a high prevalence of early consumption of whole cow’s milk by children under one year old, and it was influenced by factors such as income, education level and young maternal age. Therefore, it is necessary to raise awareness among health professionals about improving the quality of the guidelines provided during prenatal and postpartum consultations.