The authors' aim was to investigate the effectiveness of self-etch adhesives used as surface coating agents on the microleakage of conventional and resin modified glass ionomer cements. A total of 120 class V cavities were restored with either Fuji IX or Fuji II. Specimens were divided into six groups for each material according to surface coatings: uncoated, G-Coat, Futurabond, One-Coat, Clearfil S3 and Xeno III. The specimens were immersed in basic fuchsine, sectioned and scored for microleakage. Results were analysed with Kruskal-Wallis and Mann-Whitney U tests. For Fuji IX, no microleakage was observed at the occlusal margins with any of the coating materials tested, and microleakage at the gingival margins was lowest with One-Coat. For Fuji II, no microleakage was observed at either the occlusal or gingival margins for any of the materials tested. Self-etching adhesives may be used as a surface coating to reduce marginal microleakage of glass ionomer restorations.