Fetal macrosomia is associated with a 14-fold increased risk of brachial plexus birth palsy (BPBP), and is a predictor of childhood obesity. The purpose of this study was to identify the relationships between BPBP, fetal macrosomia, and childhood obesity. We retrospectively reviewed 214 children with BPBP. The average age was 8 years and 53% had a Narakas 1 grade BPBP. Overall, 49% of children were normal weight, 22% overweight, and 29% obese. Of the children with a history of fetal macrosomia, 41% were obese; a statistically significant difference. Overall quality of life scores, however, were not correlated with obesity.