NAT1 is an intronless gene on chromosome 8p21.3 encoding a 290-amino-acid-long protein showing acetyltransferase activity. Some 26 alleles of NAT1 gene have been identified in human populations. In the present study we determined the distributions of NAT1 genotypes and alleles in a sample of 201 individuals from the Turkish population in Central Anatolia. The most frequent genotypes were NAT1*4/NAT1*4 (51.74%), NAT1*10/NAT1*4 (22-39%), NAT1*11/NAT1*4(7.46), NAT1*10/NAT1*10(3.98%). Frequencies of NAT1*3, *4(wild-type), *10 and *11 alleles were 3.73%, 69.6%,17.66% and 7.2%, respectively. The frequency of NAT1 *11 was the highest amongst the populations studied so far, the other allele frequencies being close to those described in Caucasian populations.