One hundred and thirty-eight non-undercut Class V abrasion lesions were restored using glass ionomer cement overlaid by composite resin. Four techniques were used: enamel and glass ionomer acid-etched, enamel only acid-etched, ionomer only acid-etched, and neither enamel nor glass ionomer acid-etched. The restorations were examined after six months, one year and two years and evaluated for integrity and marginal staining, the latter employing a direct clinical method and a set of photographic standards. The relative failure of restorations at six months was maintained at subsequent time intervals, and at two years the failure incidence was 10, 35, 43 and 58 per cent for the above four techniques respectively. Marginal staining was most evident around those restorations for which only the glass ionomer had been etched. The results indicate that the retention of composite to etched glass ionomer is similar to that of composite to dentine using many dentine bonding agents. The several advantages of glass ionomers over dentine bonding agents are discussed.