In modern society, smoking is one of the most common harmful habits. The issue of smoking among medical students and the ways to address it are particularly relevant. The study was aimed to identify the priority factors contributing to smoking as the main harmful habit. We performed a cross-sectional study of 254 students using the tailored questionnaire, D. Horn test, and Fagerstrom test. The data obtained were processed and analyzed using the mathematical statistics methods. The findings have shown that 68.4% of students are smokers. The majority of students report negative health effects of smoking: 45% of students complain of cough, 38% complain of mucus, 52% complain of the decrease in physical endurance. Furthermore, low motivation for smoking cessation has been revealed in the majority of respondents. Vaping turned out to be the smoking type most popular among students, and the majority of respondents believe that it is harmless. The identified predominant types of smoking behavior (“support”, “craving”) suggest emotional stress. The correlation between the students’ anxious emotional state and the frequency of smoking has been found (r = 0.79). Learning problems and emotional stress are the priority factors contributing to smoking as the main harmful habit of students. Thus, the issue of smoking should be considered both in medical-biological and socio-psychological aspects. It is important to shape health-saving behavior in students through hygienic training and education.