Background: the early detection of the risk factors for low birth weight and the adequate monitoring of the women who have them allow the performance of health actions aimed to modify and control those factors.Objective: to identify the risk factors for low birth weight at the health district of the “Gustavo Aldereguía Lima” Teaching Polyclinic of Las Tunas during the years 2015 and 2016.Methods: an observational, analytical and case-control study was carried out. The universe was made up of the 1174 live births and the sample included 150 newborn babies, divided into two groups: 75 cases that were born with weight lower than 2500 grams and 75 controls with normal weight. The main risk factors identified in the country were assessed. When processing the results absolute and relative frequencies were calculated, as well as the odd ratio (OR) with its lower and upper confidence bounds for 95 % and Chi-squared.Results: the risk factors for low birth weight were maternal age lower than 20 years (OR=6,45), insufficient weight gain (OR=11,38), pregnant women nutritionally assessed with deficient weight (OR=11,53), smoking (OR=45,64) and associated diseases (OR=30,50), among them anemia and vaginal and urinary infections. Conclusions: low birth weight in the health district of the “Gustavo Aldereguía Lima” Teaching Polyclinic has a multifactorial etiology.