Introduction: The clinical management of non-carious cervical lesions is a challenge concerning restoring procedures because the lesions have non-retentive cavity shape and margins lying on dentin or cementum which are unfavorable for bonding.   Objective: To evaluate the clinical performance of two self-adhering flowable composites compared with flowable composite and resin modified glass ionomer in restoration of non-carious cervical lesions for 1 year.   Materials and Method: A total of 60 non-carious cervical lesions (15 for each material) were restored with self-adhering resin flowable composites (VertiseTM Flow and FusioTM  Liquid Dentin), flowable composite with ExciTE F dental adhesive system and resin modified glass ionomer. The outer surface of the dentinal wall was roughened with a water-cooled high-speed diamond bur. Occlusal or incisal enamel margins were beveled, and no mechanical retention was performed. The restorations were re-evaluated with the modified United States Public Health Services (USPHS) criteria at baseline, 3, 6 and 12 months.   Results: After 1 year, 14 of the 15 Vertise Flow and 12 of the 15 Fusio Liquid Dentin restorations were in a clinically unacceptable condition due to retention failure. The success rates of Vertise Flow (6.7%) and Fusio Liquid Dentin (20%) were less when compared to the success rate (80%) for the 2-step etch and rinse/Flowable composite and (60%) for the resin modified glass ionomer restorations (P-value < 0.001) Conclusion: The clinical performance of the self-adhering resin flowable composites showed higher failure rate than other restorative materials after 1 year of clinical use.