Abstract: Objective The analysis was conducted to investigate the promptness of the network reporting of infectious diseases in Ningbo city along with the factors influencing the promptness. Methods Analysis was made on the report cards of infectious diseases reported by the report and management system of disease surveillance information in Ningbo city from 2004 to 2006. Results The promptness rate of report cards of infectious diseases in Ningbo from 2004 to 2006 was 92.43%, in view of 110 662 out of 119 728 cards that were promptly reported; the promptness rate of card verification was 99.09%, in view of 118 643 promptly verified cards. The highest promptness rate of report cards in 11 counties(districts) that had a total of 119 728 report cards was 97.29% and the lowest was 87.09%, the highest promptness rate of card verification being 99.79% and the lowest 98.13%. The promptness rates of report cards in working days and holidays were 94.33% and 85.58%, respectively (P0.01), the promptness rates of card verification being 99.75% and 96.74%, respectively(P0.01). The promptness rates of report cards of medical facilities at county or higher level and those below county level were 92.38% and 92.53%, respectively(P0.05), the promptness rates of card verification being 99.06% and 99.16%, respectively(P0.05). Conclusion The report and management system of disease surveillance information in Ningbo maintained a high promptness rate of infectious diseases report since 2004 and eliminated the difference of promptness between urban medical facilities and rural ones. The promptness of infectious diseases report can be further enhanced through improving the staff's skills and maintaining the performance of cards reporting and verification in holidays.