Abstract Background The capability approach offers a comprehensive framework for the evaluation of conditions for wellbeing in terms of how well society promotes equal opportunities, skills, and the ability to lead a good life. The aim of this study was to utilize the capability approach to evaluate the real-world effectiveness of health social work among those with experienced negative life-events. Methods “Evidencing the effectiveness of health social work assessment and intervention” (Terva, 2021-2023) quasi-experimental data with mixed methods collected in real-world conditions across three hospital districts. The baseline data (intervention=266 and comparison=255) is collected and 6 months follow-up study is lasting until June 2023. Questionnaire data among participants included validated measures of perceived capabilities and background variables (age, gender, education, income) and among social workers (the evaluation of needs). Analysis of covariance (ANCOVA) while adjusting background variables at baseline and qualitative analyses will be applied. Results People with negative life-events perceived their capabilities as being lower than general adult population. These differences were especially reflected to live a healthy life and form satisfying social relationships. In baseline, the intervention group also demonstrated significantly lower capabilities compared to the comparison group. The detailed results of the real-world effectiveness of health social work on capabilities within and between intervention and comparison groups will be presented at the conference. Conclusions Our study is one of the first ones to utilize capability approach to examine real-world effectiveness of social services among those negative life events. Future studies should also include the commodities, converting factors and individual agency into the analyses and try to capture the dynamic process of the realization of capabilities and agency with a longer follow-up up to 24 months. Key messages • Capability Approach (CA) provides useful tool for evaluating effectiveness of social services in terms of promoting health and wellbeing of the customers. • CA could be utilized for developing more empowering and effective wellbeing policies targeted to the specific customer-centered needs.