Vitality is the feeling of physical and mental aliveness. Vitality benefits individual, organizational and societal well-being. This study investigates the effects of phased retirement on vitality and how this effect differs for workers dealing with work and home related strain, and by baseline levels of vitality. We used two waves of the NIDI Pension Panel Survey, collected in the Netherlands in 2015 and 2018. Data from 1,247 older workers, of whom 137 (10%) opted for phased retirement between waves, were analyzed. Vitality is assessed in three ways: (1) a composite measure of vitality, and its subcomponents (2) energy and (3) fatigue. Conditional Change OLS Regression models demonstrated that transitioning into phased retirement improved vitality and energy levels and reduced fatigue. Second, partially supporting the baseline vitality hypothesis this study found older workers with low energy levels at baseline to report greater improvements in energy after using phased retirement. The work and family strain hypotheses were largely unsupported. Nevertheless, when looking at the direct effects of work and family strain and phased retirement on vitality, we can infer that workers in demanding situations benefit from phased retirement by being able to prevent a decline in vitality by taking up phased retirement. Older workers with work and family strain are more vulnerable to a decline in vitality as they age at work. Transitioning in to phased retirement can compensate for and perhaps prevent this decline while also providing them with more relief from the burdens of balancing work and family live.