Breakfast is the first and most important meal of the day, and omitting it is associated with a greater probability of overweight and school absenteeism. The eating habits constituted in children depend on social, educational and economic factors, and they usually perpetuate into adulthood. For this reason, the most propitious stage for health promotion interventions on healthy nutrition is childhood. Specifically, in Brazil, malnutrition is relevant in children from low-income families although, currently, there are few studies that relate nutrition with the social factors. In this study, a reliability analysis of the Eating Habits of the School Population questionnaire was conducted, and the items referring to the breakfast habits and to some sociodemographic variables were selected. Subsequently, a total of 470 fourth grade pupils self-completed the questionnaire in 12 schools in Uruguaiana (Brazil). More than 50% of the mothers and more than 70% of the fathers worked in diverse areas of services and sales in stores or supermarkets. With regards to the hypothesis contrast, a significant relation was observed between the frequency of having breakfast with the father or the mother and having had breakfast (p < 0.001). This type of study favors a population analysis for the subsequent design and execution of health promotion activities.