Objective: The aim of this study was to compare the clinical efficiency of a diode laser as an adjunct to scaling and root planing (SRP) in the treatment of chronic periodontitis patients, and also to evaluate the changes in the clinical parameters such as clinical attachment level in teeth with periodontal pockets and blood reactive oxygen metabolites. Method and Materials: A total of thirty patients (mean age 38.2 years) with chronic periodontitis were selected for this study. The patients were randomly assigned into two groups of 15 patients each, as the control group and test group. The control group received only conventional SRP and the test group received conventional SRP and diode laser (GaAlAs)-assisted pocket debridement. The clinical parameters (Plaque Index, bleeding on probing, probing pocket depth, and clinical attachment level) were recorded at baseline and day 60, and the serum levels of reactive oxygen metabolites were estimated at baseline, day 30, and day 60 for both the groups. Results: When the groups were compared, there was statistically significant improvement in Plaque Index score, decrease in bleeding on probing and probing pocket depth, and gain in clinical attachment level (P .001) in both the groups from baseline to day 60. There was significant reduction in reactive oxygen metabolites in both the groups from baseline to day 30 and day 60 (P .001). However no statistically significant changes were present between the treatment groups from baseline to day 60 in terms of clinical parameters and blood reactive oxygen metabolites. Conclusion: From the results observed in this study it can be concluded that use of diode laser as an adjunct to SRP did not provide any significant difference compared to use of SRP alone in terms of clinical parameters and reactive oxygen metabolites. Keywords: periodontal disease, reactive oxygen species, serum