Purpose: To retrospectively evaluate the clinical outcomes of subgingival debridement (e.g. scaling and root planing, SRP) and application of either a chlorhexidine chip (PerioChip, PC) or Arestin (AR) minocycline microspheres in patients with chronic periodontitis during supportive periodontal treatment (SPT). Materials and Methods: Patients diagnosed with moderate to severe chronic periodontitis who were treated with SRP and a slow-release device during SPT were evaluated (total n = 53; n = 37 received PC, n = 16 received AR). Clinical measurements at baseline, 3, 6 and 12 months included changes in probing pocket depth (PD), bleeding on probing (BOP) and clinical attachment level (CAL). Results: Both treatments led to a reduction in PD and gain of CAL. AR showed higher improvements in pockets of ≥7 mm compared with PC. In contrast, PC was more effective in 5-6 mm PD. At one year following treatment, both treatments reduced the need-for-surgery index (95% to 100%) of the sites at baseline to 30% for AR and 42% for PC, with no differences between PC and AR. Conclusions: In patients enrolled in SPT, the use of both PC and AR in conjunction with subgingival mechanical debridement represents an effective treatment modality for improving the clinical outcomes and reducing the need for surgery. Keywords: Arestin, chlorhexidine chip, minocycline microspheres, PerioChip