The purpose of this study was to determine the prevalence of dental erosion in an adult population in Switzerland. 391 randomly selected persons from two age groups (26-30 and 46-50 yr) were examined for frequency and severity of erosion on all tooth surfaces. Information was gathered by interview about lifestyle, dietary and oral health habits. For facial surfaces 7.7% of the younger age group and 13.2% of the older age group showed at least one tooth affected with erosion with involvement of dentin (grade 2). 3.5 teeth per person in the younger and 2.8 teeth per person in the older age group were affected. Occlusally, at least one severe erosion was observed in 29.9% of the younger and 42.6% of the older sample with 3.2 and 3.9 erosion-affected teeth per person, respectively. 3.6% of the younger age group and 6.1% of the older age group showed slight lingual erosion on the maxillary anterior teeth. Severe lingual erosions were scarce. Data from interviews and multiple regression analyses revealed that acids from beverages are significantly associated with presence of erosion.