In most of the industrialised world, the proportion of older and retired people in the population is continuously increasing. This will have budgetary implications for maintaining the welfare state, because the active working section of the population must fund the non-active and old population. Aim: The overall aim of this thesis was to obtain knowledge about older workers' work and life situation in association with their planning and decision to retire from working life. Method: The thesis includes one qualitative and three quantitative studies conducted in Sweden. Result: Self-rated health was found to be a better measure than diagnosed disease of whether older workers believed they could work until 65 years or beyond. Health seems not to be a general impediment to working in old age if older workers are satisfied with their work situation and have enough time and opportunities to recover from fatigue. In one of Sweden's most hazardous work environments, older workers were not injured significantly more often than younger workers. Good mental and physical work environment, moderate working pace and working time, and the right competence and possibility for skills development were factors determining whether older workers believed they can extend their working life. Attitude to older workers in the organisation, motivation and work satisfaction were factors determining whether older workers want to extend working life. Health, personal economic incentives, family/leisure pursuits and attitude to pension in society affected both whether people believed they can and wanted to extend their working life. In their final retirement decision, older workers considered: i) their possibility to balance and adapt functional ageing and health to a sustainable work situation; ii) their economic situation; iii) possibilities for social inclusion and coherence; iv) and possibilities for meaningful activities. Whether these requirements were best fulfilled in or outside working life determined the decision to continue working or to retire. Conclusion: If it is desirable for society that people will to extend their working life, both the "can work" and the "want to work" factors need to be met. It is important to provide a good fit inside working life. This requires a focus not only on older workers, but also on organisations and managers in order to provide incentives that keep older workers in the work force. Keywords: ageing, older worker, retirement planning, retirement decision, motivation, meaningful activity, social inclusion, macro, meso, micro, work environment, working life, work ability, work injury, health, public health, diagnosed disease, self-rated health, organisation, basic premises for work, hardware in work, software in work Sammanfattning Antalet äldre i befolkningen ökar i förhållande till andra åldersgrupper. Detta beskrivs medföra en ekonomisk utmaning för samhället och att fler äldre behöver skjuta upp sin ålderspension.Avhandlingen bygger på fyra studier med det övergripande syftet att bidra t...