BACKGROUND: Weight gain in pregnancy is an important monitoring tool for the obstetrician. Weight change in pregnancy has been found to have impact on maternal and neonatal outcome. Patients who gain weight within the recommended range by the Institute of Medicine (IOM) are more likely to have the best obstetric outcome. OBJECTIVE: To determine the pattern of weight gain in pregnancy and their associated maternal and fetal outcomes. METHODOLOGY: A prospective observational study involving 135 pregnant women with singleton pregnancy recruited between 24 and 26 weeks gestation and followed up to delivery was conducted in the University of Benin Teaching Hospital. A data extraction sheet was used to get relevant data. The data collected was stored, coded and analysed using statistical package of the social sciences (SPSS) version 20. Qualitative variables were compared using chi-square test or Fisher’s exact test. Pearson correlation test was performed to understand the relationships between quantitative variables. For all statistical test, a ρ value of < 0.05 was considered significant.