Abstract: The paper shows the results of underreporting survey of the infant death in the Zhejiang Provincial Disease Surveillance System in December, 1996. The underreporting rate of birth was 0.32% based on the health card in the maternal period and the underreporting rate of infant death was 0.04%. The underreporting rate of birth in hospital was 0.04%. The infant death rate (in obstetric departments) was 0.02% and in pediatric departments was 6.9%. The underreporting rates of birth and infant death in residents were 7.37% and 21.74% respectively. The main causes of underreporting infant death were that 60% was township hospitals failing to report and 40% was parents failing to report. The adjusted birth rate was 10.71‰ while the adjusted infant death rate was 23.88‰ residents..