Immunological alterations have been implicated in the etiopathogenesis of vitiligo. The aim of this study was to determine peripheral lymphocyte subpopulations and interleukin-2 receptor (IL-2R) in patients with vitiligo. Forty-five vitiligo patients (24 female, 21 male) and 34 healthy controls (I I female, 23 male) were included into the study. Eight (17.8%) of the patients had the segmental type, and 37 (82.2%) had generalized vitiligo. The disease was active in 25 (55.6%) patients; the other 20 (44.4%) patients had static vitiligo. Flow cytometry was used to determine the percentages of total T-lymphocytes, B-lymphocytes, helper/inducer T cells, suppressor/cytotoxic T cells, natural killer (NK) cells, activated T cells and interleukin-2 receptor (IL-2R) with the use of CD3, CD19, CD4, CD8, CD 16, HLA-DR and CD25 monoclonal antibodies, respectively. The mean value of helper T cells showed a significant difference (p=0.01) between the two groups with the value being 32.5% in patients and 38.1% in control subjects. CD4/CD8 was significantly lower in vitiligo patients (p=0.04). There was also a statistically significant difference in the mean percentage of activated T cells between vitiligo patients and control subjects (4.7 and 8.1, respectively; p=0.001). No statistically significant differences were found when the values were compared between segmental and generalized vitiligo patients, or between active and static cases. In conclusion, T helper/inducer cells, CD4/CD8 ratio and activated (HILA-DR+) T cells are decreased in vitiligo patients, suggesting a role for changes in cellular immunity.