Background: The north-Norwegian population of Sør-Varanger lives close to 2 Russian nickel smelters. Objective: We studied the importance of the local nickel pollution, as well as ear piercing and atopic dermatitis, on the prevalence of nickel allergy in Sør-Varanger. Methods: We patch-tested 1767 adults who were randomly selected from 2 different cross-sectional studies; in Sør-Varanger and the reference city of Tromsø, which has no nickel-polluting industry. Results: Nickel allergy was diagnosed in 27.5% and 31.1% of the women in Sør-Varanger and Tromsø, respectively, and in 5.1% and 5.0% of the men. In women, ear piercing was a strong risk factor (relative risk = 3.30; 95% confidence interval = 2.01 to 5.43). A history of atopic dermatitis was not associated with nickel sensitization. We found no increased risk of nickel allergy in Sør-Varanger compared with Tromsø in adjusted multivariate analyses. Conclusion: The high prevalence of nickel allergy found in Sør-Varanger could not be attributed to pollution from the nearby nickel industry.(J Am Acad Dermatol 1999;40:726-35.)