The aim of this multicenter study was to evaluate the 3-year performance of a resin-modified glass ionomer cement in primary molars. A total of 174 class II restorations were placed in 85 children by 6 dentists. The restorations were evaluated during a 3-year period using slightly modified USPHS criteria (van Dijken 1986). Of the 174 restorations 161 were evaluated after 1 year, 121 after 2 years and 68 after 3 years. A total of 81, restorations exfoliated or was extracted during the study. The cumulative failure rate after 1, 2 and 3 year was 8.1%, 11.7% and 19.8% respectively. The main reasons for failure were secondary caries and loss of retention.