Aim: The aim of the present study was to evaluate the effect of sardine (Sardinella gibbosa) fish extract on papain induced osteoarthritis in rats. Methodology: In this study 30 wistar rats were randomly selected and divided into five groups. Group-1 (-ve Control), Group 2 (+ve control), Group 3 (Calcium 75 mg/kg as standard), Group 4 (Sardine extract 30 gms/kg), Group 5 (15 gms/kg sardine extract). Osteoarthritis was induced in the right knees of all the groups of rats except negative control by injecting 0.2 ml (4%) of papain solution with 0.1 ml (0.03M) of cystein as activator. All groups were left for development of osteoarthritis. Rats were sacrificed on day 1, 2, 7, 14, 21 & 28 days of post papain injection. Results: Estimation of calcium and phosphorus in fish extract was carried out by Atomic absorption spectrophotometer. The percentage inhibition of knee thickness of sardine fish extract and Calcium groups were found to be 68% and 77% respectively. Various haematological parameters like RBC count and Hb, WBC count and ESR were recorded. Parameters like blood glucose, urea, globulin, creatinine, total protein, and albumin were calculated. Histopathological studies of knee joints of rats were also carried out. Conclusion: Sardinella gibbosa fish extract at a dose level of 30 gm/kg p.o., exhibited reduction in osteoarthritis due to the rich source of Ca & selenium and maintained the normal haematological and biochemical parameters in papain induced osteoarthritic rats