The authors assessed the risks of drug-related death, suicide, and homicide after release from New York City jails in 155,272 people who were incarcerated anytime from 2001 through 2005 and examined whether the mortality rate was associated with homelessness. Using jail records matched with death and single-adult homeless registries in New York City, they calculated standardized mortality ratios (SMRs) and relative risks. After adjustment for age, sex, race, and neighborhood, the risks of drug-related death and homicide in formerly incarcerated persons were 2 times higher than those of New York City residents who had not been incarcerated in New York City jails during the study period. These relative risks were greatly elevated during the first 2 weeks after release (for drug-related causes, SMR = 8.0, 95% confidence interval (CI): 5.2, 11.8; for homicide, SMR = 5.1, 95% CI: 3.2, 7.8). Formerly incarcerated people with histories of homelessness had higher rates of drug-related death (RR = 3.4, 95% CI: 2.1, 5.5) and suicide (RR = 2.1, 95% CI: 1.2, 3.4) than did persons without such histories. For individuals who died of drug-related causes, longer jail stays were associated with a shorter time until death after release. These results suggest that jail- and community-based interventions are needed to reduce the excess mortality risk among formerly incarcerated people.