An investigation on the health status of 79 male preparatory school students lodging at a dormitory in Japan was carried out by questionnaire on lifestyles, subjective symptoms and mental status, as compared with two control groups: 73 medical students and 36 new employees. About 83 % of them slept less than 6 hours and 70 % of them did not exercise. Many students are troubled with back pain or lumbago(47%), sensation of incomplete bladder emptying(l6%), loss of visual acuity(55%) and eye fatigue(65%). Self-rating depression scale score of preparatory school students was not significantly higher than those of the control groups. The lifestyles of preparatory school students found to be very restricted and strained. However, no significant differences on mental adverse health effects was found among three groups.