Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked red blood cell enzymopathy common in malaria endemic areas. Individuals affected by this disease show a wide variety of clinical signs including neonatal jaundice. In this preliminary report we describe the heterogeneity of G6PD deficient gene in neonatal jaundice in the Malay population in Kelantan. Thirteen G6PD deficient Malay neonates with hyperbilirubinemia were subjected to mutation analysis of the G6PD gene for known candidate mutations. Molecular defects were identified in the 13 patients studied. Though all of these were mis-sense mutations, identified nucleotide changes were heterogeneous. Six patients were found to have a C to T nucleotide change at nucleotide 563 of the G6PD gene (C563T), corresponding to G6PD Mediterranean; three cases had a single nucleotide change at T383C (G6PD Vanua Lava), two cases had G487A (G6PD Mahidol) and two cases had G1376T (G6PD Canton). These findings suggest that there are heterogeneous mutations of the G6PD gene associated with neonatal jaundice in the Malay population in Kelantan.