objective: to assess breakfast habits and conditioning factors among university students from the department of biochemistry and biological sciences, and establish if there is a relationship between the quality of breakfast and body mass index (bmi). method: a descriptive cross- sectional study was carried out. 130 students of both sexes (18-21 years old) were surveyed. a selfadministered questionnaire was used to show the foods consumed at breakfast and assess their quality. it was considered "breakfast of good quality" the one that included at least one food from each one of dairy, cereals and fruit groups. the students′ weight and height were measured to calculate their bmi. results: the distribution of population according to bmi was as follows: 82% were classified as normal weight, 5% underweight, 12% overweight and 1% obesity. 95% of the students said they had breakfast, but only 15% had a "good quality breakfast". in the case of the students that did not have breakfast, the main reasons were lack of time and hunger when getting up. 71% had a mid-morning collation. in most of the cases, the choice of foods for the collation was not adequate to complete the breakfast. the prevalence of overweight and obesity among university students was not associated with the quality of breakfast. conclusion: the results indicate that it is necessary to improve the quality of students' breakfast. it is important to encourage a responsible choice of the food consumed at breakfast and emphasize the importance of complementing it with an adequate collation if the breakfast was not of good quality.