Musculoskeletal disorders (MSDs) are the main cause of occupational diseases in Estonia and Europe. The number of MSDs has increased with the increasing number of computer workers and the increasing workload overall. In the current paper, the survey of 295 workers in Estonian enterprises is carried out to clarify the reasons of occupational stress. The causes of occupational stress are non-ergonomically designed workplace, social and human factors. The main questionnaires used were KIVA and GPSnordic. The conclusion is that KIVA questionnaire alone is too mild to point out the risk factors. The comparison with other questionnaires has to be carried out.