Objective:  To systematically review the evidence of effectiveness of surgical vs. non‐surgical therapy for the treatment of chronic periodontal disease. Methods:  A search was conducted for randomized controlled trials of at least 12 months duration comparing surgical with non‐surgical treatment of chronic periodontal disease. Data sources included the National Library of Medicine computerised bibliographic database MEDLINE, and the Cochrane Oral Health Group (COHG) Specialist Trials Register. Screening, data ion and quality assessment were conducted independently by multiple reviewers (L.H., F.H., L.T.). The primary outcome measures evaluated were gain in clinical attachment level (CAL) and reduction in probing pocket depth (PPD). Results:  The search provided 589 s of which six randomized controlled trials were included. Meta‐analysis evaluation of these studies indicated that 12 months following treatment, surgical therapy resulted in 0.6 mm more PPD reduction (WMD 0.58 mm; 95% CI 0.38, 0.79) and 0.2 mm more CAL gain (WMD 0.19 mm; 95% CI 0.04, 0.35) than non‐surgical therapy in deep pockets (>6 mm). In 4–6 mm pockets scaling and root planing resulted in 0.4 mm more attachment gain (WMD −0.37 mm; 95% CI −0.49, −0.26) and 0.4 mm less probing depth reduction (WMD 0.35 mm; 95% CI 0.23, 0.47) than surgical therapy. In shallow pockets (1–3 mm) non‐surgical therapy resulted in 0.5 mm less attachment loss (WMD −0.51 mm; 95% CI −0.74, −0.29) than surgical therapy. Conclusions:  Both scaling and root planing alone and scaling and root planing combined with flap procedure are effective methods for the treatment of chronic periodontitis in terms of attachment level gain and reduction in gingival inflammation. In the treatment of deep pockets open flap debridement results in greater PPD reduction and clinical attachment gain.