BACKGROUND: No studies to specifically determine the prevalence of contact allergy to acrylates/methacrylates in patch tested populations have been published. OBJECTIVES: To determine the prevalence of acrylate/methacrylate allergy in all patients tested to the baseline patch test series. METHODS: Five acrylate/methacrylate allergens (2-hydroxyethyl methacrylate, methyl methacrylate, ethylene glycol dimethacrylate, triethylene glycol diacrylate, and 2-hydroxypropyl acrylate) were included in the baseline series for at least 2 years in Malmö and Singapore. RESULTS: Thirty-eight patients in total had reacted to acrylate/methacrylate allergens in the baseline series during the study period in both populations. In Malmö, there were 26 (1.4%) patients with positive patch tests to acrylate/methacrylate allergens, 14 of whom had relevant reactions. In Singapore, there were 12 (1.0%) patients with positive patch tests to acrylate/methacrylate allergens, but only 1 had relevant reactions. If we had not added acrylate/methacrylate allergens to the baseline series, we would not have patch tested 13/26 (50%) of the positive reactors in Malmö and 11/12 (92%) of the positive reactors in Singapore. The overall proportion of missed positive reactors would have been 24/38 (63%). CONCLUSIONS: The prevalence of acrylate/methacrylate allergy in our patch tested dermatitis populations is 1.4% in Malmö and 1.0% in Singapore.