Introduction. Medical students experience significant psychological stress and are therefore at higher risk of using sedatives. There are currently no studies describing the prevalence of sedative drug use among medical students in Saudi Arabia. The aim of this study was to evaluate the prevalence and factors associated with sedative drug use among medical students in Saudi Arabia. Materials and Methods. A cross-sectional convenience sampling study gathered data by anonymous questionnaire from students enrolled at the King Saud University College of Medicine in 2011. The questionnaires collected data regarding social and demographic variables, sleep patterns, and the use of stimulant and sedative drugs since enrollment. Sedatives were defined as any pharmaceutical preparations that induce sleep. Results and Discussion. Of the 729 students who returned questionnaires, 17.0% reported sedative drug use at some time since enrollment. Higher academic year, lower grade point average, regular exercise, fewer hours of sleep per day, poorer quality of sleep, and the presence of sleeping disorders were found to be significantly associated with sedative drug use. Conclusions. Further study is required to increase our understanding of sedative drug use patterns in this relatively high-risk group, as such understanding will help in the development of early intervention programs.