The Sexual Behavior Survey (ERAS) is a cross-sectional, self-administered, voluntary online survey conducted among men who have sex with men (MSM); four rounds have been conducted since 2017 (2019, 2021, 2023). The aim of this article is to describe trends in chemsex use across these national surveys and the characteristics of MSM who engage in chemsex based on ERAS 2023. Since 2017, chemsex use has remained stable over time, regardless of the indicator used. Use during the most recent sexual encounter stood at 5% in 2017 and 6% in 2023, and at 12% in 2021 and 13% in 2023 during the 6 months prior to the survey. Compared to participants who do not engage in chemsex, those who do are more often aged 25–45, urban, unemployed, and financially less well-off; they are attached to gay social circles and values of sexual performance, are HIV-positive or HIV-negative, and use pre-exposure prophylaxis (PrEP). They are more likely to have multiple partners and are less consistent in using condoms during anal intercourse with casual partners. Chemsex is associated with behaviors that carry a high risk of HIV and other sexually transmitted infections (STIs), as well as signs of psychosocial distress that require further exploration. Services tailored to chemsex use, addressing the challenges of harm reduction, sexual health, and psychosocial care for MSM, must be implemented to ensure appropriate prevention and interventions that promote the well-being of this population.