This cross-sectional study conducted between March and June 2006 examined stress at work and work ability of 180 people with different workplaces within an oil company. Office, laboratory, and oil-field workers were invited to complete the "Occupational Stress Assessment Questionnaire - the Oil Industry Version and Work Ability Index (WAI) Questionnaire". The overall response rate was 69.4 %, and the final sample size was 125 workers who completed the questionnaires (57 office, 41 laboratory, 27 oil-field workers). Office, laboratory, and oil-field workers differed significantly with respect to age (