Abstract: Objective: Although reduced care engagement has been linked to increased mortality for persons with serious mental illness (SMI), there have been limited investigations into specific mortality causes for this group. This study evaluates the effects of care disengagement on mortality cause and time until death in Veterans with SMI.Method: A total of 3300 Veterans with SMI lost to Veterans Affairs care for more than 1 year were contacted by providers who attempted treatment reengagement. Fisher’s Exact Tests evaluated associations between mortality cause and reengagement status, and a Cox proportional hazard model evaluated the association between reengagement and survival.Results: During the study, 146 (4.6%) patients died. A lack of reengagement was associated with increased noninjury death [odds ratio (OR)=1.64], increased cancer-based mortality (OR=4.76) and an average of 97.4 fewer days of life.Conclusions: Care reengagement may support medical care management and reduce preventable medical mortality for Veterans with SMI.