Background: Substance abuse and its associated problems are a global concern. Substances, such as tobacco, alcohol, cannabis, and various allopathic drugs have been widely abused by students for various reasons despite their known ill effects. Aim and objective: Prevalence and pattern of substance abuse among the medical students in a medical college of Kolkata during coronavirus disease (COVID-19) pandemic. Material and methods: It is a hospital-based, cross-sectional study. This is carried out in ESI-PGIMSR, ESIC Medical College and Hospital, Joka, Kolkata. Data were collected after obtaining due consent from the Institutional Ethics Committee of our institute. Students pursuing MBBS constitute the study population. A structured questionnaire created by Google forms, designed, and validated in-house was circulated online to obtain the information. Results: Details of the demographic pattern showed 72 of them were female students and the rest were male and their age group varied between 21 and 23 years. Thirty-four of them were staying in the rural area whereas the rest were urban pupils. Most of the participation came from 1st-year students (83) and the least came from final year (4th or 3rd Prof Part 2) students. The number of participants was only 10. A significant statistical association was found between male gender and marijuana abuse (p = 0.043), and male gender with smoking (p = 0.002). The association of the status of being a hostelite with marijuana abuse (p = 0.015), alcohol abuse (p = 0.065), and with smoking (p = 0.012) was also found to be statistically significant. The prevalence of smoking and marijuana abuse was observed to progressively increase from the 1st year (3.61%) to the final year (smoking = 40%, marijuana = 50%). Conclusion: Further research is needed from Eastern India to understand patterns of substance use among medical students, to identify important determinants, and reinforce protective factors.