BACKGROUND: Illegal drug markets are shaped by multiple forces, including local actors and broader economic, political, social, and criminal justice systems that intertwine to impact health and social wellbeing. Ethnographic analyses that interrogate multiple dimensions of drug markets may offer both applied and theoretical insights into drug use, particularly in developing nations where new markets and local patterns of use traditionally have not been well understood. This paper explores the emergent drug market in Kisumu, western Kenya, where our research team recently documented evidence of injection drug use. METHODS: Our exploratory study of injection drug use was conducted in Kisumu from 2013 to 2014. We draw on 151 surveys, 29 in-depth interviews, and 8 months of ethnographic fieldwork to describe the drug market from the perspective of injectors, focusing on their perceptions of the market and reports of drug use therein. RESULTS: Injectors described a dynamic market in which the availability of drugs and proliferation of injection drug use have taken on growing importance in Kisumu. In addition to reports of white and brown forms of heroin and concerns about drug adulteration in the market, we unexpectedly documented widespread perceptions of cocaine availability and injection in Kisumu. Examining price data and socio-pharmacological experiences of cocaine injection left us with unconfirmed evidence of its existence, but opened further possibilities about how the chaos of new drug markets and diffusion of injection-related beliefs and practices may lend insight into the sociopolitical context of western Kenya. CONCLUSIONS: We suggest a need for expanded drug surveillance, education and programming responsive to local conditions, and further ethnographic inquiry into the social meanings of emergent drug markets in Kenya and across sub-Saharan Africa.