A prospective screening program of 11,161 newborns identified twenty-one infants who had postaxial type-B polydactyly (a prevalence of one in 531 live births). Sixteen infants (76 per cent) had bilateral postaxial type-B polydactyly. Eighteen infants (86 per cent) had a family history of the anomaly. The racial prevalence was one in 143 live births of black infants and one in 1339 live births of white infants. The duplicated small fingers were treated in the newborn nursery with suture ligation at the base of the pedicle. One infant had a second procedure to remove a blackened digit that remained firmly attached one month after the initial treatment. No other complications occurred. Fifteen patients (twenty-eight fingers) were reexamined at an average age of twenty months (range, twelve to thirty-seven months). Twelve fingers (43 per cent) had a residual bump, with an average diameter of two millimeters (range, one to six millimeters). Despite the residual bumps, all of the parents were satisfied with the cosmetic result.