Background: Osteoarthritis (OA) is an age-related disorder and is often described as a chronic degenerative disease. Prevalence rates is estimated that 9.6% of men and 18% of women aged ≥ 60 years have symptomatic OA worldwide whereas in India it is 22% to 39%. Foot Posture Index (FPI) is a diagnostic clinical tool aimed at quantifying the degree to which a foot can be considered to be pronated, supinated or neutral position. Aim of the study: To determine correlation between Foot Posture Index and Knee Osteoarthritis in Elderly individuals. Result: The Karl Pearson correlation co-efficient(r) for the above study is 0.43, R squared value is 0.18 and the two tailed p value is <0.0001 and thus the result shows extreme significance. Conclusion: The study concluded that, there is positive correlation between knee osteoarthritis (OA) and foot posture index. The abnormal foot posture was commonly seen in patients with OA Knee grade 3 and 4.