The objective of this study was to assess the prevalence of modifiable risk factors of the major non-communicable diseases (NCDs) among medical students. A cross sectional study was conducted at three randomly selected medical colleges in the Kathmandu Valley in Nepal. All third-year medical students (n = 191) participated in the study. A total of 62.3 % of the respondents were male, and 37.7 % were female. The mean age of the respondents was 21.5 ± 1.0 (SD) years. A total of 20.4 % (n = 39) of the medical students were current tobacco users and 50.8 % (n = 97) have ever consumed alcohol. The majority (85.6 %) of the medical students did not consume the daily recommended amount of fruits and vegetables. A total of 30.9 % (n = 59) of the medical students were involved in low level of physical activity and 42.9 % (n = 82) were involved in moderate level of physical activity. This study showed a high prevalence of risk factors of major NCDs among medical students and interventions are needed to change the unhealthy behaviour of medical students being role models in society.