In the Chinese postal system, letters are sorted manually using a sorting frame, consisting of vertical and horizontal arrays of pigeon-holes of different dimensions. Letter sorting is a time consuming and a mentally intensive task involving repetitive movements of shoulder and hand muscles. Musculoskeletal complaints and disorders of the lower back, shoulder and hand occur frequently among the letter sorting workers. A total of 293 letter-sorters (71 males and 222 females) from Beijing Postal Sorting Office were subjected to a general health check-up including musculoskeletal disorders coupled with administration of a questionnaire. The worker's daily work load was evaluated by counting the number of letters sorted in each pigeon-hole in the sorting frame and also by considering their arm movements and body postures. The workplace dimensions were also measured. Results revealed that 62.1% of the workers complained of low back pain, 78.5% of shoulder pain and 48.8% of hand pain. A high percentage of workers seemed to have mental intensive symptoms, such as, headache, dizziness and drowsiness. Almost 25% of the female wokers indicated irregularity in their menstruation. An improved ergonomic design of the sorting frame is recommended.