We aimed to investigate the co-morbid effects of maternal obesity, Gestational Diabetes Mellitus (GDM), and GDM treatment options on maternal and neonatal outcomes in an inner-city population. This is a retrospective chart review study of singleton mothers with new diagnosis of GDM and their infants during a 3-year period. During the study period, 356 women ages 13-48 years with GDM gave birth to 180 males and 175 females. Majority of mothers were African American (50.8%) and had Medicaid insurance (75.8%). Obese mothers constituted 48.3% of the study population, had a higher prevalence of pregnancy induced hypertension/preeclampsia, more commonly were managed with medication and delivered by C-section than non-obese mothers. Infants of obese GDM mothers had significantly higher mean birth weight, lower mean blood glucose, and were less at risk for Small for Gestational Age (SGA). In obese mothers, heaviest mothers had infants with higher bilirubin levels than less heavy mothers. We also observed a high rate of feeding difficulty in infants of GDM mothers (12.4%). Our study emphasizes the burden of maternal obesity as a major risk factor for both maternal and neonatal poor outcomes in the context of GDM and calls for further prospective and interventional research.