We estimated the prevalence of overall sexualized drug use (SDU) and of chemsex in particular, assessed patterns of drug use, and identified subpopulations of men who have sex with men (MSM) where SDU and chemsex are more frequent. Using data from an online survey of 9407 MSM recruited during 2016 in 7 European countries, we calculated the proportion of participants who reported SDU and chemsex (mephedrone, met...