Work ability is the physical and psychological capacity of workers to meet the demands of a job; it declines with age, and the effect is multiplied in a sedentary job. Early detection of workers at risk would help to improve their functional capacity and work efficiency. To identify factors and develop a prediction model for low work ability among sedentary aging office workers. In this case-control study, work ability among sedentary aging workers was evaluated using a Work Ability Questionnaire (WAQ). The worker's age, gender, BMI, marital status, years at work, diabetes, hypertension, diagnosed medical condition, musculoskeletal problems, medicine intake, menopause, physical activity, sedentary work behaviour and six job-related tasks were recorded. Multiple logistic regression was performed, and the odds ratio was calculated for the variables assessed. One hundred and fifty seven sedentary aging workers were assessed for 19 independent factors. BMI and years at work in the demographic domain, diagnosed medical condition and intake of medicine in the health-related domain and handgrip strength in the task domain were found to have a statistically significant odds ratio for poor work ability. The study identified factors influencing work ability among sedentary aging workers and a prediction model was developed.