Low birth weight (LBW) is one of the most common public health problems both nationally and globally, because of its association with the increased risk of neonatal morbidity and mortality. The main objective of this research was to identify the incidence and maternal factors associated with LBW. A descriptive, cross-sectional study was carried on in 198 neonates and their mothers in the neonatal area of the José Carrasco Arteaga Hospital in the city of Cuenca. Newborns weighing less than 2500 grams were considered with LBW. Data were expressed in absolute and relative frequencies. Statistic Chi-square (X2) was used to establish the relationship between low neonatal weight and maternal risk factors. A value of p<0.05 was considered statistically significant. The incidence LBW was 11.1%. In the statistical analysis, the factors associated with LBW were low weight gain during pregnancy (p=0.001) and number of pregnancies (p=0.03). No significant association was observed between LBW and prenatal controls, intergenesic period, gestational diabetes, pre-eclampsia and the presence of diseases in the gestational period. The number of cases of low birth weight children was similar to those found in other studies. The true factors associated with LBW were low weight gain during pregnancy and the number of pregnancies.