The current study investigated the clinical effectiveness of three adhesives and the use of retention form in Class V resin composite restorations of the non-carious cervical lesion (NCCL) over a two-year period. One-hundred and fifty NCCLs in 39 patients were restored with resin composites according to six experimental protocols combining the presence or absence of retention form and three adhesives: ScotchBond Multi-Purpose (MP, 3M ESPE), an experimental adhesive (EX, Vericom) and Adper Prompt (AP, 3M ESPE). All restorations were evaluated at baseline, 6, 12 and 24 months. Modified United States Public Health Service (USPHS) criteria were used to evaluate the restorations. MP was found to have significantly superior marginal adaptation than AP in cumulative logistic regression analysis (odds ratio, 2.12; 95% confidence interval, 1.05-4.31; p = 0.0397). In analysis using the Pearson's Chi-square or Fisher's Exact Test to compare the clinical performance of restorations with and without retention form, EX with retention form showed a significantly higher retention rate at two years than that without retention form (p = 0.0089). Restorations with retention form also showed significantly less marginal discoloration than those without retention form in all three adhesives (p = 0.0336).