Abstract: Objective To understand the underreporting of notifiable communicable diseases by medical institutions in Wenzhou and develop strategy for the standard communicable disease reporting. Methods The analysis was conducted on the survey data of communicable disease underreporting from 2009 to 2011 in Wenzhou. Results During this period, 467 cases were underreported in 29 293 cases of 24 communicable diseases in class B and C, the underreporting rate was 1.59%. The underreporting showed no increase trend (χ2=3.37, P>0.05). The underreporting rate in private hospitals or clinics was highest, followed by township health centers (χ2=761.70, Pχ2=3.97, PConclusion The annual underreporting rate of communicable diseases was ≤2% from 2009 to 2011. It is still necessary to strengthen the training and supervision of communicable disease reporting, especially in private hospitals or clinics and township health centers.