Osteoarthritis (OA) is a joint disease that most commonly accompanied with pain and joint deformity which eventually leads to disability. Burden of OA will be accounted second in women and fourth in men in Iran. Most therapies of knee osteoarthritis are symptomatic treatment. Recently, strontium ranolate are used as a new agent for handling of post menopausal osteoporosis and provided reduces in hip and vertebral fractures risks. Beneficial effects of this treatment are showed in spine OA as well. This study was designed to evaluate short-term effects of strontium ranolate on treating of knee OA in Iran. Study was performed as a randomized double blind clinical trial. Symptomatic knee OA cases at Kellgren – Lawrence based stages I, II and III were enrolled in study following exclusion of systemic disease as well as joint disease. These patients randomly divided into 2 groups and each group was treated with placebo and Strontium ranolate at the dose of 2 mg per day. Then cases were followed for 12 weeks via Visual Analog Scale (VAS) and Western Ontario and McMaster universities (WOMAC) questionnaires associated with subsequent statistically analyzes. Statistically significant differences in the rate decline of pain, stiffness, functionality and eventually total scores as well as VAS scores were revealed between strontium ranolate and placebo therapy. Given the proven positive effects, strontium ranolate recommended as one of treatment bases in association with weight loss and muscles physiotherapy as well as healthy use of joints.