Abstract Background: Knee pain is considered one of the main causes of referral to the Radiology Department. Many of the cases have abnormalities within or around the joint following an acute injury or chronic symptomatology. Ultrasound is a reliable method for detection of injury to the tendons, ligaments, and muscles of the knee joint with its capability to evaluate peri-articular lesions. The periarticular structures are best suitable for ultrasonography evaluation including peri articular masses, joint effusion and bursae. Aim of Study: The goal of our study is to evaluate role of high resolution ultrasonography in assessment of knee peri articular disorders compared to MR imaging. Patients and Methods: Our study included 61 patients between March 2018 and April 2019 with 14 patients having bilateral knee joint examinations. They included 37 females and 24 males with their ages ranging between 11-70 years. All of them suffering from painful knee joint with peri-articular lesions. Patients were referred to the Radiology Department at Kasr Al-Aini Hospital after full clinical examination to evaluate their knee joints using US and MRI. Results: High resolution ultrasonography had sensitivity and specificity ranging from 83 to 100 and 100% respectively with Positive Predictive Value (PPV) of 100%, Negative Predictive Value (NPV) and accuracy above 95%. Conclusion: The high correlation rate between the results of US and MRI have shown that in patients with knee joint peri-articular lesions, US is an effective alternative/ compli-mentary method of examination in detection of knee joint peri articular injuries, cystic and solid mass lesions.