Purpose: This article describes the prevalence of facial ache vulgaris in adolescents of Arequipa, Peru, in relation to ethnic characteristics. Methods: This was a cross-sectional study of 2214 healthy adolescents, 55.83% male and 44.17% female, 12-18 years old. Based on visual inspection, the severity of acne was classified into four grades. The adolescents studied were divided into three ethnic groups: whites, Mestizos, and Indians. Results: Less than half of the adolescents (41.69%) had acne: 33.74% grade 1, 5.19% grade 2, 2.12% grade 3, and 0.63% grade 4. The prevalence of acne varied from 16.33% at 12 years to 71.23% at 17 years. At age 12 and 13 years, the prevalence of acne was higher in females, with the trend reversing over age 14 years. The overall prevalence of acne was significantly less in Indians (27.97%) than in Mestizos (43.08%) or whites (44.47%). More acne was found in postmenarche (39.90%) than in premenarche (20.99%). This trend was also true for the severity of acne. Conclusions: The prevalence of acne in the adolescents of Arequipa is significantly less than in Caucasians. Peruvian Indians have significantly less acne than Peruvian whites or Mestizos. It seems that ethnicity is an important predictor of not only the prevalence, but also the severity of juvenile acne vulgaris in this sample.