Ample speculation and some evidence suggests that the decline in homicide rates since the early 1990s was partially attributable to declining levels of drug market activity. This analysis explores that explanation, along with an alternative: the strength of the drug market-lethal violence relationship has weakened over time. We outline several conceptual reasons to expect period-specific differences in the drug market-homicide relationship. These include the aging of market participants, shifts in the normative and transactional climate of markets, and changes in structural factors affecting the magnitude of the relationship between drug market indicators and homicide rates (such as socioeconomic disadvantage). These arguments are evaluated for a sample of large US cities. The results generally show a pattern of attenuation in the drug markethomicide relationship and lead us to conclude that part of the homicide decline is likely due to a drop in the amount of drug market activity, some of it is attributable to the aging of drug market participants, and some appears to be due to unmeasured factors which may have created a "kinder and gentler" drug market.