A review of all autopsied infants weighing less than 2251 grams (34 cases) who expired on the third to seventh days of life during the six year period from 1971 to 1976 failed to reveal any cases of kernicterus. This contrasts with an incidence of 64% (9 of 14) in low-birth-weight infants from the same neonatal intensive care unit during the period 1966-67 (Pediatrics 45:906, 1970). The infants in the two series were not significantly different with regard to their birth weights, Apgar scores, perinatal complications, or non-neurologic postmortem findings. The only significant difference between these two groups of infants was a lower mean peak serum bilirubin concentration in the 1971-76 series (11.1±4.0 mg/dl vs. 8.7±3.4 mg/dl), resulting from the use since 1970 of lower serum bilirubin concentrations as criteria for exchange transfusion and the use of phototherapy since 1974. The prevention of excessive hyper-bilirubinemia as well as the development of more sophisticated intensive care of the neonate in recent years may be responsible for the elimination of kernicterus in the 1971-76 series of infants weighing less than 2251 grams.