the ultrasonography is safe rapid and very effective method for evaluation of soft tissue lesions especially by using high frequency transducer. The authors analyzed ultrasonographic findings of 49 cases of the soft tissue lesions of extremities which were proven clinically and surgically and/or pathologically in Korea Univer-sity Hospital for recent 5 years. the results were as follows: 1, Of the 49 cases 27 cases were male and 22 cases female. 2. Infectious conditions were 22 cases benign tumor 6 cases malignant tumor 6 cases and miscellanous 15 cases. 3. The accurate diagnosis of nature of the lesions was possible in all cases except tuberculous tendinitis of Achilles tendon in infectious conditions (21/22). except neurilemmoma in benign tumors(5/6) except soft tissue synovial sarcoma and liposarcoma in malignant tumor (4/6) and all cases of misellanous conditions (15/15) with clinical symptom and plain X-ray film. 4. By using high frequency transducer for extremity lesions. we obtained precise location size shape and internal structure of the lesions and guide for aspiration and/or biopsy.