Mutations of the AE1 (SLC4A1 ) gene that codes for band 3, the bicarbonate/chloride anion exchanger in both the renal collecting duct and the red cell, have been shown to cause many cases of distal renal tubular acidosis (dRTA). We performed mutation analysis on 5 children with dRTA seen at the Philippine General Hospital to determine whether or not AE1 mutations are responsible for this chronic debilitating kidney condition. All children fulfilled the clinico-chemical criteria for the disease. Rickets and nephrocalcinosis were present in all of them. All of the subjects presented with abnormal blood films typical of Southeast Asian Ovalocytosis (SAO). By means of DNA sequencing, the 5 children were found to have the mutant allele, Gly701 ’!Asp (G701D). Four (4) subjects are homozygous for the mutation; one patient is a compound heterozygote with the other allele being a SAO deletion (SAOÄ 400-408). The latter follows a recessive mutation only when the other allele is an AE1 mutation. The Met31’!Thr (M31T) polymorphism was also present in the 5 children. The study concludes that AE 1 mutations are responsible for dRTA among this group of Filipino children. G701D is the most common AE 1 mutation that presents either as a compound heterozygote with SAO, or in homozygous form. We recommend mutation analysis and blood film examination among children diagnosed with distal renal tubular acidosis.