In most western countries, nickel is the most common contact allergen among young women. In 1991, Denmark implemented a statutory order calling for the reduction of exposure to nickel in nickel-plated items in close contact with the skin. In a retrospective analysis, a comparison is made of the number of positive patch tests to nickel seen in a private practice of dermatology before and after this statutory order was implemented. From 1 January 1986 to 31 December 1989, 35 of 1135 (3.1%) men patch tested and 628 of 3024 (20.8%) women patch tested had positive reactions to nickel. From 1 January 1996 to 31 December 1999, 48 of 1104 (4.3%) men and 424 of 2193 (19.3%) women had positive patch tests to nickel. During the 1st period, 155 of 702 women under the age of 20 (22.1%) had positive patch tests to nickel, compared to 54 of 324 (16.7%) during the second period (p<0.05). The most likely explanations of this decrease in nickel sensitivity are reduced exposure to nickel and increased public awareness of the risk of nickel sensitization.