Objective: to know the relationship between pregnant women 's nutrition and weight gain in the different socioeconomic strata. Introduction: Pregnancy is a period of change, during which an excessive increase in weight leads to imbalances of both the mother and the fetus, with unpredictable future consequences, so that the socioeconomic evaluation of dietary habits according to the different strata will help guidance in prenatal consultation. Materials and methods: An epidemiological, analytical, cross-sectional and non-experimental study was conducted with a total population of 101 pregnant women in the period June to August 2017. A questionnaire was applied to identify the weight gained during pregnancy, the level of knowledge food and nutrition as well as socioeconomic status. Statistical analysis was performed with software Epi Data version 3.5.4, and ANOVA test for statistical significance, in which p < 0.05 were significative. Results: The mean age was 24 ± 5 years, with a gestational age between 22 and 34 weeks, socioeconomic status predominated Graffar III (46%) with a high-calorie, low-fat diet and ypoproteic and unbalanced in remaining strata; with a prepregnancy weight of 59 ± 11 kg, 67 ± 11 gestational Kg, and a monthly gain between 0,2 - 2 kg. Conclusions: There is a relationship between maternal nutrition and weight gain with the social stratum; an alteration of any of these factors could change the health and welfare of both mother and child. Nevertheless, we couldn’t find specific causal association with maternal diseases. We recommend prenatal weight control and at least once every three months nutritional control and monitoring weight gain with specialists in the field.