Although numerous mechanisms are involved in vitiligo pathogenesis, few studies correlate N-acetyltransferase 2 to this disease. To assess the N-acetyltransferase 2 (rs1799929) gene and its serum levels in vitiligo patients. In this case-control study, 65 vitiligo cases were compared to 65 age- and sex-matched healthy controls. Serum NAT2 levels and the NAT2 gene polymorphism (rs1799929) were evaluated using ELISA and real-time PCR, respectively. Serum N-acetyltransferase 2 levels were significantly lower in cases than in controls, 1.24 ± 0.31 vs. 2.01 ± 0.46 (p = 0.001). CC genotype was more dominant in controls (58.5%) than in cases (20%). TT and CT genotypes were more dominant in cases (30.8% and 49.2%) than in controls (13.8% and 27.7%), respectively (p = 0.001). The C allele was more prominent in controls (72.3%) than in cases (44.6%) while the T allele was more dominant in cases (55.4%) than in controls (27.7%) (p = 0.001). N-acetyltransferase 2 slow acetylator phenotype (TT genotype) was higher in cases (30.8%) than in controls (13.8%) and rapid acetylator phenotypes (CC and CT genotypes) were higher in controls (86.2%) than in cases (69.2%) (p = 0.035). Slow acetylator genotype (TT) of NAT2 gene (rs1799929) and low serum levels of NAT2 enzyme might play a role in the susceptibility and pathogenesis of vitiligo.