OBJECTIVE We evaluated the relationship between maternal body mass index (BMI) and death or bronchopulmonary dysplasia (BPD). We hypothesized that in extremely low birth weight (ELBW; BW < 1,000 g) infants, the risk of death or BPD would be greater if the maternal BMI deviated further from the ideal BMI of 24. METHODS ELBW infants admitted to AdventHealth Neonatal Intensive Care Unit (NICU) between calendar years 2012 and 2017 were included in this retrospective observational study. BPD was defined as continuous supplemental oxygen use at 36 weeks post-menstrual age. RESULTS There was no association between the deviation of maternal BMI from the ideal of 24 and the composite outcome of death or BPD (6.9 ± 6.7 vs. 7.06 ± 6.6, pp = 0.966). However, there was a lower risk of death with a higher maternal BMI (p = 0.024). BPD was also associated with a higher maternal BMI (p = 0.045). CONCLUSIONS Maternal BMI was not associated with the composite variable of death or BPD in ELBW infants. The lack of association was due to the contrast between high BMI and a lower risk of death and a higher risk for BPD. CONCLUSIONS · Maternal BMI was not associated with the composite outcome of death or BPD.. · Elevated BMI was associated with a higher risk of BPD.. · Elevated BMI was associated with a lower risk of death..