Using a new dataset on leader health, we present and test five hypotheses derived from a selectorate theory account of how chronic illness interacts with political institutions, especially winning coalition size, to help shape the probability and timing of regular and irregular leader depositions. The analysis shows that, especially in small coalition — autocratic — political systems, the expectation that an incumbent will die soon, and so not be able to deliver future private rewards to her coalition of supporters, greatly increases the likelihood that the leader will be overthrown. The study also compares selectorate expectations with an alternative view, that sickly leaders are deposed because they can no longer produce effective policy, measured in terms of economic growth. As predicted by selectorate theory, sickly leaders significantly improve growth in an effort to stay in power for their short remaining lifetime. The analysis offers a new view on an important aspect of political instability, namely leader removal.