Red-cell enzymes and reduced glutathione (GSH) were assayed on cord blood in 307 Indian neonates. On follow-up, 20 of them developed pathologic jaundice. Of these, six had red-cell enzyme/GSH deficiency, seven had associated non-enzymatic causes of jaundice, and in the remaining seven the cause could not be diagnosed. In 41 other neonates, there was enzyme/GSH deficiency without pathologic jaundice. The degree of enzyme deficiency had no relation with jaundice. Red-cell enzyme/GSH deficiency state in neonates was associated with pathologic jaundice more frequently (six of 47; 12.8%) than in the absence of such deficiency (14 of 260; 5.4%). None of the jaundiced patients had very high levels of bilirubin nor needed exchange blood transfusion. There was no reduction in haemoglobin level in the enzyme/GSH deficient group with jaundice in comparison with non-deficient jaundiced neonates or normal subjects. The incidence of red-cell enzyme/GSH deficiency appears to be high in Indian neonates; however, the majority of them do not precipitate pathologic jaundice.