This study was conducted to compare the specialty preference and factors that affect choices of medical specialties between medical college students and graduate medical school students. A self-administered questionnaire was conducted in 563 medical students, and 482 (graduates: 199, undergraduates: 283) responded (response rate, 85.61%). The students completed a brief survey, which included 39 items that sampled their demographic data, career choice, and factors that influenced their choice. Most students in medical college and graduate medical school preferred clinical medicine. Graduate medical school students preferred internal medicine, pediatrics, and family medicine. In contrast, medical college students preferred neurology, family medicine, and psychiatry. Important factors that affected the selection of specialties were seniors' advice, advice of other students, clerkship experiences, and specialty experiences. This result shows that there are differences in the factors that affect the selection of medical specialties between medical college students and graduate medical school students. But, the opportunity to explore future careers and to consult their choice of specialty, in accordance with the needs and characteristics of individual students, must be provided for all medical students.