Background: Chemsex, involving intentional psychoactive substance use to enhance sexual experiences, poses significant health risks to men who have sex with men (MSM). In India, limited research exists on chemsex dynamics within MSM communities, particularly in stigmatized urban settings like New Delhi. Objective: This study explored socio-behavioural patterns, community dynamics, and health impacts associated with chemsex among MSM in New Delhi, investigating motivations, practices, risk behaviours, and support needs. Material and methods: An exploratory qualitative study was conducted from April 2022 to June 2023 following COREQ guidelines. Twenty-one MSM participants aged ≥18 years who engaged in chemsex within six months were recruited through snowball sampling. Data were collected via semi-structured telephone interviews (n=15) and anonymous Google Forms (n=6). Thematic analysis identified patterns in experiences and health outcomes. Results: Chemsex initiation typically occurred in social settings and was episodic. Participants reported using crystal methamphetamine, MDMA, heroin, and cocaine, often combined with alcohol as a social/contextual precursor. High-risk practices included needle sharing and unprotected sex, increasing HIV and hepatitis transmission risks. Violence including robbery and sexual assault was reported. Significant health impacts included deteriorating physical health, increased anxiety, guilt, and regret. Privacy concerns and social stigma led to concealment of behaviours. Strong peer pressure influenced engagement, while quit attempts were frequently unsuccessful due to addiction complexities and inadequate support systems. Conclusions: Chemsex among MSM in New Delhi involves complex psychosocial dynamics with severe health consequences. Urgent implementation of harm reduction strategies, accessible mental health services, and non-judgmental healthcare approaches is essential to address this vulnerable population's needs.