Background: In this rapidly spreading infectious disease era, the study of sexually transmitted infections among the high risk group population especially Men having sex with Men(Viraj v patel et al 2012) needs special attention as it pave the way for realising the social and psychological behavior of the individual and society. But the data on the socio–psycho behaviors and STIs among MSM in India were meagre and is the need of hour to plan the strategies of STI/HIV prevention (AIDS Care. 2013) Aims and objective: To study the pattern and epidemiological aspects of Sexually transmitted infections in men having sex with men(MSM) attending STI clinic in Govt Vellore medical college, Vellore, Tamilnadu.Materials and methods: Retrospective observational study of pts who were registered at STI clinic, Govt. Vellore Medical College, Vellore between January 2017 and Dec 2018.Inclusion criteria: All male patients with history of sexual contact with men (Men having sex with Men )attended our opd were included.Exclusion criteria:Female patients and Male patients with history of sexual contact exclusively with females were excluded Results: 127 pts were identified to be Men having sex with Men.55% were of rural and 45% were of urban origin. Predominant age group was 20 to 40 yrs. Viral infections seem to be the predominant STI in MSM Conclusion: There is a high prevalence of STIs among men having sex with men which is a very important factor for STI/HIV transmission in society. HIV and anogenital warts were found to be the most common Viral STIs among MSM