Objectives To study the relation between night urinary free cortisol (UFC) ex-cretion and hypertension in youth. Methods Nighturinary free cortisol excretion and blood pressure & itsrelated factor were measured in 188 young people.Results In young men with hypertension the 8 h’snight UFC excretion was significantly higher than thatin the group with normal blood pressure 21.57 ± 6.28μg/8hvs 10. 54 ± 5. 46μg/8 h (P ＜0.05). Inagroup of young people with positive family history ofhypertension, the night UFC excretion was much higherthan that in the group with negative family history ofhypertension. Men excrete much more night UFC thanwomen (12.73±5.85 μg/8hvs7.80±4.15 μg/8h, P ＜ 0. 05). Conclusions There is an associationbetween hypertension and high 8h’s night UFC excre-tion; furthermore, there is gender difference in nightUFC excretion.