Objectives To analyze the heart rate variability(HRV)in children with dilated cardiomyopathy(DCM). Methods Heart rate variability was examined in children with DCM(n = 23)and healthy controls(n = 23). Holter recordings were used to analyze the heart rate(HR),time domain and frequency domain indexes of HRV. Statistical analysis was performed by using the SPSS11.0 software. Results Compared with the control group, minimal HR was significantly high while SDNN,SDANN,pNN50,TP and ULF were obviously low in DCM group(P 0.05=. Maximal HR,VLF,LF,HF,LF/HF in DCM group were slightly higher than those in control group while rMSSD in DCM group was slightly lower than that in control group(P 0.05). Conclusions The function of autonomic nervous system in children with DCM was damaged seriously.