An epidemiological study reported that low serum cholesterol is one of the causes of cerebral hemorrhage. Furthermore, differences in the Apoprotein E (ApoE) genotype influence the amount of low density lipoprotein in serum. The value of standardized mortality ratio (SMR) for cerebral hemorrhage or infarction in residents of Kikai island (KI) is higher or lower than 100, respectively. The aim of this educational activity is to assess whether our lectures on “prevention of stroke” ─(1) relationship between cholesterol and stroke, (2) test items involved in cholesterol of serum and role of lipoprotein, (3) relationship between gene and disease, and (4) prevention of disease by diet─were effective for junior high-school students (JHS) in KI. To be improve their understanding of lecture (3), we performed genetic analysis (for ApoE polymorphism) using DNA extracted from their hair roots. Although we also conducted lectures after the results of the analysis, the pretest (40.7%) and posttest (50.0%) indicated that lecture (3) had been difficult for JHS. The total scores for the posttests for second- and third-year JHS (72.5% and 80.3%, respectively) were significantly higher than those for the pretests for second- and third-year JHS (49.6% and 55.9%, respectively). However, for first-year JHS, the total scores for posttests (63.0%) and pretests (61.7%) were not significantly different. Based on these results, we concluded that our lectures facilitated a substantial understanding about the “prevention of stroke” among JHS and were educationally beneficial for second- and third-year JHS, in particular.