Nickel allergy was studied in a sample of 1st-year university students starting their studies in 1995. A total of 296 subjects (72%) of 413 invited participated in the clinical examination, and 284, 96 male and 188 female, were patch tested (69%). A history of nickel sensitization was enquired for. Prick tests and serum specific IgE levels were determined. Occurrence of atopic dermatitis, hand eczema, and current exposure to metals were recorded. Nickel allergy was encountered in 39% of all female students, in 42% of females with pierced skin, and in 14% of females without pierced skin. The corresponding figures for males were 3%, 7% and 3%. In the multiple regression analysis, the risk factors for nickel allergy were female sex (OR 8.1, p<0.01), current metal exposure at examination (OR 4.1, p<0.01) and skin piercing (OR 3.6, p<0.05). Positive prick tests or elevated IgE levels to common allergens were not significantly associated with nickel allergy. In female students, the prevalence of nickel allergy has increased from 13% in 1986 to 39%. The prevalence among males has remained low at 3%. The results indicate that, in addition to skin piercing, current metal contacts are important risk factors for nickel allergy. This finding gives support to the EU Nickel Directive.