Purpose: To evaluate the 5-year clinical performance of Dyract in small Class I cavities in non stressbearing areas. Methods: On 36 patients, 87 restorations needing small cavity preparations were performed. The lesions were diagnosed macroscopically with a probe. They involved shallow fissures, and had reached dentin but the lateral spread was limited and localized in dentin. Cavities were designed to be on non stress bearing areas. Cavities' average facio-lingual width were prepared to be 1/3 or less than the intercuspal width. At baseline, 1-, 2-, 3-, 4- and 5-year recalls, the restorations were evaluated according to the modified Ryge criteria by two calibrated, experienced examiners. Results: None of the restorations was lost and retention rate was 100% at the end of 1 year. After 2 years, one restoration (1.2%) had to be replaced due to caries lesion adjacent to its margin and the rate of retention was 98.8%. At the 3-year recall, four restorations, at the 4-year, one restoration and at the 5-year, one restoration had caries lesions adjacent to their margins and the cumulative retention rates were 94.2%, 92.9% and 91.5% respectively. Significant differences were detected between all of the evaluation periods in regard to color match rate (P= 0.00001), with the exception of rate between the baseline and 1 year evaluations. In regard to the marginal discoloration rates, there were statistically significant differences (P= 0.00001) between all of the evaluation periods with the exception of rates between the baseline and 1-year, 3- and 4-year, and 4- and 5-year results. Except for the failed restoration, no other restoration was clinically unacceptable in regard to color match, wear or loss of anatomic form, marginal discoloration, caries, marginal adaptation and surface texture.