While over-indebtedness has emerged as a new social risk among Europeans as a consequence of economic recessions, its associations with health and disability are poorly understood. This study utilises longitudinal, register-based data to assess the associations of over-indebtedness with disability retirement. Severely over-indebted people were identified from the Finnish credit information register. For each over-indebted person, one matched control was retrieved from the population register (total N: 54,494). Register data on socio-demographics, health-related factors and pensions were used to analyse the incidence of disability pensions due to different diagnoses among over-indebted people and their controls during the period 1995–2009 using Cox regression analysis. The analyses showed that over-indebtedness was strongly associated with the risk of disability retirement in all diagnostic groups. The associations were stronger among women than among men. The adverse effects of over-indebtedness on health and disability should be acknowledged. In addition to standard socio-demographic indicators, debtor status may add to our knowledge of the predictors of poor health. Policymakers should adopt measures to prevent over-indebtedness and to overcome its harmful effects.