The purpose of the present study was to evaluate the clinical quality over 4 years and the longevity over 10 years of 77 Mastique laminate veneers (DeTrey, Dentsply). The veneers were bonded to incisors and canines with a light-cured composite resin, using the acid-etch technique, and examined every 1/2 year in accordance with USPHS criteria. Anatomic form and marginal adaptation were rated excellent in more than 50% of the veneers throughout the study. Moderate surface wear was seen in most of the veneers after 4 years of service. Marginal discoloration and color match were recorded as not acceptable in 20% of the veneers at the 4-year control. No significant difference was found in the gingival index between veneer and control teeth. The cumulative retention rate was 40% after 4 years and 20% at the 10-year recall. Owing to the high frequency of spontaneous loss, Mastique laminate veneers cannot be recommended as permanent restorations.