Background: Melasma is a pattern of facial pigmentation that affects upper lip, cheeks, forehead and chin. The disease is seen mainly in 30-55 year old women, and may be regarded as a physiological change in pregnancy. Its etiologic nature is still unknown. Objective: To determine the prevalence of melasma in women in Ardebil city. Patients and Methods: The study was cross sectional-descriptive study done on 855 women in Ardebil city in 2002. Sampling method was cluster and 855 women in the age range of 12-85 years in 25 health services (From each family one woman over 11 years) were randomly selected and necessary information have been collected by a questionnaire. Descriptive and analytic statistics were used to analyze data in SPSS program. Results: The prevalence of melasma among total participants was 39.5% and 9.5% of melasma cases were pregnant women. The distribution of hyperpigmentation was mainly centrofacial (64.7%), and in 40.8% cases there was a positive familial history for melasma. Conclusion: Melasma is a common disease in Ardebil, and abundant search is necessary to understand the etiology and treatment of this disease.