Objective To dynamic monitoring the changes of serum cortisol,adrenocorticotropic hormone (ACTH) in children with sepsis and servere sepsis,and to assess it's relationship with clinical features.Methods Thirty children with sepsis were enrolled in this study from Sep 2010 to Jan 2011 in our hospital,and were divided into severe sepsis group (n =10) and sepsis group (n =20).The serum cortisol and ACTH were analysed in acute and recovery period respectively in both two groups,and compared with 10 non-sepsis children as control group.Results In the acute period,the level of serum cortisol in severe sepsis group [ (33.97 ±6.83) μg/ml ] was significantly higher than those in sepsis group [ (26.30 ± 10.43) μg/ml]and control group [ ( 19.06 ± 6.91 ) μg/ml ] ( P ＜ 0.01 ) ; the level of serum ACTH in severe sepsis group [ (25.47 ± 9.41 ) pg/ml ] was significantly higher than those in sepsis group [ ( 15.52 ± 5.85 ) pg/ml ] and control group [ (9.16 ± 3.02 ) pg/ml ] ( P ＜ 0.01 ).Conclusion Stress response exists in the early period of sepsis,and the levels of serum cortisol and ACTH are increased significantly.The levels of serum cortisol and ACTH are positive correlation with the severity of diseases,and they could be used as serious index and a marker for evaluating prognosis in children with sepsis.