BACKGROUND: Sexualized drug use (SDU) refers to use of any psychoactive substance before/during sexual intercourse. Chemsex is a subset of SDU, which is defined as the use of some specific psychoactive substances (methamphetamine, mephedrone, γ-hydroxybutyrate, ketamine and cocaine) before/during sexual intercourse. SDU and chemsex are prevalent among gay, bisexual and other men who have sex with men (GBMSM). This study investigated uptake and willingness to use pre-exposure prophylaxis (PrEP) among a sample of GBMSM in Hong Kong with experience of SDU in the past year. METHODS: A total of 600 GBMSM were recruited by convenient sampling through outreaching in gay venues, online recruitment and peer referral. Participants completed a cross-sectional anonymous telephone interview. This study was based on a subsample of 580 GBMSM self-reported as HIV negative/unknown sero-status. RESULTS: Of the participants, 82 (14.1%) and 37 (6.4%) had experience of SDU and chemsex in the past year. The prevalence of PrEP uptake was 4.0% among all participants and 14.6% among those with experience of SDU in the past year. Among GBMSM with experience of SDU in the past year who were not on PrEP (n = 70), 67.1% were willing to use daily oral PrEP in the next 6 months. Multivariate logistic regression models showed that positive attitudes toward PrEP (AOR: 2.37, 95%CI: 1.47, 3.82), perceived support from significant others to use PrEP (AOR: 9.67, 95%CI: 2.95, 31.71), and perceived behavioral control of using PrEP (AOR: 19.68, 95%CI: 5.44, 71.26) were significantly associated with higher willingness to use PrEP. CONCLUSION: GBMSM with experience of recent SDU are potentially good candidates of PrEP implementation. This group of GBMSM reported high prevalence of uptake and willingness to use PrEP. Perceptions related to PrEP based on the Theory of Planned Behavior were significantly associated with willingness to use PrEP.