Simvastatin (SMV) is a specific competitive inhibitor of 3-hydroxy-2-methylglutaryl coenzyme A reductase that promotes bone formation. The present clinical trial was designed to investigate the effectiveness of 1.2 mg SMV as a local drug delivery system and as an adjunct to scaling and root planing (SRP) in the treatment of aggressive periodontitis (AgP). A total of 68 intrabony defects from 24 patients with AgP were treated either with 1.2 mg SMV gel or placebo gel. The subjects were randomly assigned to SRP + placebo (group 1; n = 12) or SRP + SMV (group 2; n = 12). Clinical parameters were recorded at baseline and at 3 and 6 months and included bleeding index, Plaque Index, probing depth (PD), and clinical attachment level (CAL). At baseline and after 6 months, radiologic assessment of bone defect fill was done. The mean decrease in PD at 6 months was 1.14 ± 0.04 mm and 3.78 ± 0.62 mm in groups 1 and 2, respectively. Significant gain in mean CAL was found between the groups (P .05). Furthermore, significantly greater mean percentage of bone fill was found in group 2 (34.01%) compared to group 1 (2.62%). Locally delivered SMV provides a comfortable method to improve clinical parameters and promotes bone formation.