The Achilles tendons of 114 selected patients were examined using a high-resolution linear scanner at 7.5 mHz in real-time mode. Twelve ruptures of Achilles tendons, 16 soft tissue tumours, 36 inflammatory and 27 degenerative alterations were sonographically scanned. The remaining patients were known to have normal findings. Clinical, radiographic and intraoperative findings were evaluated for comparison. The sensitivity of sonography was 87%. In all cases of Achilles tendon rupture the sonographic diagnosis proved correct. Our findings demonstrate the possibility of differentiating Achilles tendon alterations with high specificity and sensitivity via real-time sonography. Clinical examination of patients with lesions of Achilles tendon should always be followed by sonography.