The leukemias are the most common form of childhood cancer. The same kinds of leukemia are found in children and in adults. Because the radiologist is involved in the initial diagnosis, the evaluation of response to therapy an demonstration of complications, it is important that he understands the clinical and radiological features of leukemia. This report is a clinical and radiological review of 80 cases who visited to Chonnam National University Hospital from January 1977 to 1981. The results are summarized as follows. 1. Most prevalent group of age was between 10 to 14 years old(25%) and male was affected more frequently than female with the ratio of 1.4:1. Acute form of leukemia was 95% and acute myelocytic leukemia was more frequent than acute lymhocytic leukemia. 2. Pallor with anemic conjuntiva was the most prominent clinical manifestation of the leukemia. Fever was the most common symptom in childhood leukemia and general weakness was the most common in adult leukemia. 3. Hematologic examination revealed marked anemia(hemoglobin level was less than 8.0gm/100ml in 65%). In 17.5% the leukocyte count was less than 5, 000/cu.mm and more than 10, 000/cu.mm in 65%. Platelet count was less than 50, 000/cu.mm in 23.8% and between 50, 000 and 150, 000/cu.mm in 43.7%. 4. The abnormal findings in chest X-ray films were observed in 35%. Pneumonia(18.8%) was the most common and lymphadenopathy(17.5%), pleural effusion(12.5%), leukemic infiltration(3.75%), pulmonary congestion and pulmonary edema(3.75%) were descending order of frequency. 5. The abnormal findings in long bone X-ray films were observed in 75% and the bone changes were more frequent in acute lymphocytic leukemia(57.1%) than in acute myelocytic leukemia(17.9%). Metaphyseal transverse radiolucent band(75.0%) was the most common and osteolytic lesion(60.7%), periosteal reaction(35.7%), osteosclerosis(7.1%) were descending order of frequency. 6. The common sites of bony changes were femur(75%), tibia(57.1%), humerus, radius and ulna in order of frequency. 7. In 35.7% of the cases who complained of bone or joint pain with abnormal findings in long bone X-ray films, leukocyte count was less than 5, 000/cu.mm.