BACKGROUND: Occupational self-efficacy (OSE) is an appropriate adaption capability to react to continuous changes in work life today. While self-efficacy is an important component in work context, there is less knowledge regarding older workers' OSE. OBJECTIVE: This study examined the relationship between work ability, OSE and work engagement among a middle-aged workforce, and whether there were any differences between age groups and between professionals in different work context. METHODS: Data were collected by questionnaire, which included Work Ability Index (WAI), Occupational Self-Efficacy Scale, and Utrecht Work Engagement Scale. RESULTS: A total of 359 home care workers and engineers (response rate 43%) participated. The average age was 54 (SD±5.3) years, 69%were women. The results of logistic regression analyses revealed an association between WAI, OSE (OR 0.66; 95%CI 0.52 to 0.86) and work engagement (OR 0.61; 95%CI 0.47 to 0.78). Higher OSE and work engagement were related to higher work ability. No difference in OSE (5.9; ±0.8) between professional groups was seen, but the home care workers scored considerably higher work engagement (5.1; ±0.9) than the engineers (4.5; ±1.3). CONCLUSIONS: Improving OSE could be worthwhile to support work ability among middle-aged workers, despite dissimilarities in work context and educational level.