BACKGROUND: Patch testing detects delayed-type sensitizations and may show changes in prevalence over time. OBJECTIVES: To compare sensitization prevalence to our baseline series allergens during the years 2000-2004 to results from 1990 to 1994. METHODS: We analysed baseline patch test series allergens from 2000 through 2004. RESULTS: 4094 individuals were patch tested to the baseline series (mean age 45.4 years, males 41.7%). The highest sensitization rates were found for nickel sulfate (19.3%), fragrance mix (10.4%) and Myroxylon pereirae (7.8%). Compared to 1990-1994, methylchloroisothiazolinone (and) methylisothiazoline (MCI/MI) and neomycin sulfate sensitization decreased and lanolin alcohol, thiuram mix and ammoniated mercury sensitization increased. CONCLUSIONS: Current sensitization rates are similar to those across Europe. Reduced sensitizations to MCI/MI and neomycin sulfate and increased sensitizations to thiuram mix and ammoniated mercury chloride may well be because of changes in exposure. The current group comprises a higher proportion affected by leg dermatitis and may thus explain the higher sensitization to lanolin alcohol. Comparing patch results over time shows important changes in sensitization prevalence.