The objective of this study is to identify individual-level factors and health venue utilization patterns associated with uptake of pre-exposure prophylaxis (PrEP) and to evaluate whether PrEP uptake behavior is further diffused among young men who have sex with men (YMSM) through health venue referral networks. A sample of 543 HIV-seronegative YMSM aged 16-29 were recruited in 2014-2016 in Chicago, IL, and Houston, TX. Stochastic social network models were estimated to model PrEP uptake. PrEP uptake was associated with more utilization of health venues in Houston and higher levels of sexual risk behavior in Chicago. In Houston, both Hispanic and Black YMSM compared to White YMSM were less likely to take PrEP. No evidence was found to support the spread of PrEP uptake via referral networks, which highlights the need for more effective PrEP referral network systems to scale up PrEP implementation among at-risk YMSM.