Working postures in 116 microwave-oven assemblers were measured and analysed using postural load scores of body parts in 137 workers complaining the cervicobrachial syndrome (CBS). The relationship between postural load scores of body parts and the grades of CBS was observed. Results were summarized as follows. 1. The height of work-table and work-seat, the thumb tip reach, the shoulder angle, the elbow angle and the forward bending angle of body trunk exceeded the recommended level and therefore they seemed to impose increased static postural loads on muscles of neck and shoulder as well as static and/or dynamic load on arm and hand muscles. 2. The postural load score of shoulder in grade II was significantly lower than that in grade III-2 and IV and those of elbow, neck+shoulder, elbow+wrist and upper extremity were significantly lower in grade II than in grade Iv. These results suggested that the awkward working postures were associated with the occurrence of CBS as well as the severity of CBS.