Crack cocaine markets were associated with substantial increases in violence in the U.S. during the 1980s and 1990s. Using cross-city variation in the emergence of these markets, we show that the resulting violence has important long-term implications for understanding current levels of murder rates by age, sex and race. We estimate that the murder rate of young black males doubled soon after crack’s entrance into a city, and that these rates were still 70 percent higher 17 years after crack’s arrival. We document the role of increased gun possession as a mechanism for this increase. Following previous work, we show that the fraction of suicides by firearms is a good proxy for gun availability and that this variable among young black males follows a similar trajectory to murder rates. Access to guns by young black males explains their elevated murder rates today compared to older cohorts. The long run effects of this increase in violence are large. We attribute nearly eight percent of the murders in 2000 to the long-run effects of the emergence of crack markets. Elevated murder rates for younger black males continue through to today and can explain approximately one tenth of the gap in life expectancy between black and white males.