Background Vitiligo is an acquired depigmenting disorder. The exact etiopathogenesis of vitiligo is not fully understood. Vitamin B12 and folic acid levels are decreased in vitiligo, which are important cofactors required for the metabolism of homocysteine (Hcy). Consequently, the Hcy level increases in the circulation. Therefore, it is possible that increased Hcy plays a role in the destruction of melanocytes. Objective To determine the role of Hcy, vitamin B12, and folic acid in the pathogenesis of vitiligo. Patients and methods Thirty-five patients of both sexes with vitiligo and 35 age-matched healthy controls were included in the study. After excluding factors that may affect serum Hcy levels, blood samples from patients and controls were obtained for Hcy, vitamin B12, and folic acid determination by an enzyme immunoassay. Results The mean serum level of Hcy was significantly higher in patients with vitiligo than in the controls (17.77 ± 7.72 vs. 11.81 ± 3.41 μmol/l; P < 0.05), whereas the mean level of vitamin B12 was lower in patients with vitiligo than in the controls (208.64 ± 66.73 vs. 304.7 ± 89.9 pg/ml; P < 0.05). There was no statistically significant difference in the folic acid level in patients and controls (8.42 ± 2.06 vs. 9.39 ± 2.38 ng/ml; P > 0.05). Conclusion Elevation of serum Hcy level might be a precipitating factor for vitiligo in predisposed individuals. Hcy level may represent a new biomarker of the extent of vitiligo. Elevation in Hcy is associated with relative deficiencies of vitamin B12, suggesting that aggressive supplementation may benefit vitiligo patients. Keywords: Folic acid, homocysteine; vitamin B12, vitiligo