The present study aimed to design a sitting stool for fish processing worker to reduce the postural stress during work. The study was conducted on 74 male and female fish processing workers selected randomly. The Musculoskeletal Disorder (MSD) of the subjects was assessed by the modified Nordic Questionnaire method. The body joint angles were measured by a digital goniometer. The results revealed that MSD was highly prevalent in lower back region in both male (78.57%) and female (93.47%) workers. The results of body joint angles suggested a high degree of forward bending during work. Efforts were made to design a sitting stool considering the human factors of the users to reduce the postural problems. The stool was designed by considering 5th and 95th percentile values of different anthropometric dimensions of the male and female workers. Paired comparison tests were employed to determine optimum dimensions of the stool for ensuring the compatibility of the physical characteristics of the stool with human body. From the results of paired comparison test and anthropometric characteristics of the users, physical dimensions of the sitting stool were settled for final designing. From the results, the height of the stool was determined separately for male and female workers. In the suggested design the height of the seat was 25cm for male and 20cm for female where the length and depth of the seat were 40cm and 32cm respectively for both sexes.A mechanical system was incorporated in the design so that the same stool could be used by the male and female workers. Subjective evaluation indicated that most of the subjects (>75%) rated the seat as good or very good. The joint angle study with suggested seat showed improved working posture.