Aims and objectives: The aim of the study was to estimate the levels of osteopontin (OPN) in gingival crevicular fluid (GCF) of subjects with clinically healthy periodontium and subjects with gingivitis and chronic periodontitis and also to investigate the effect of treatment (scaling and root planing) on osteopontin levels in GCF in chronic periodontitis subjects. Materials and methods: A total of 45 subjects in the age group of 20-45 years were selected. The subjects were divided into three groups as Group I (Healthy), Group II (Gingivitis) and Group III (Chronic periodontitis). Group IV consisted of 15 subjects of group-III, who were treated with non-surgical approach. Samples of GCF were collected at the initial visit in Group I, Group II and Group III subjects. Scaling and root planing was performed for Group III subjects. After 8 weeks, GCF was collected from the same site of the subjects in Group III. The concentration of osteopontin was determined using a human osteopontin enzyme immunometric assay (EIA) kit. Results: The highest mean OPN concentration in GCF (12.733 __ampersandsignmu;g/ml) was observed in Group III and the lowest mean OPN concentration (1.946 __ampersandsignmu;g/ml) was observed in Group I. After treatment, the mean concentration of OPN in GCF decreased from12.733 __ampersandsignmu;g/ml to 5.690 __ampersandsignmu;g/ml (Group IV). OPN levels in GCF increased proportionally with the progression of periodontal disease and reduced significantly following treatment. Conclusion: The results observed in this study indicate that osteopontin could serve as a potential biomarker of periodontal disease progression.