Abstract: Objective To understand the etiological and epidemiological characteristics of infectious diarrhea in Zhenhai of Ningbo, Zhejiang province. Methods The stool samples of diarrhea patients were collected for the detections of Salmonella, Shigella, Diarrheagenic Escherichia coli, Vibrio cholerae, Vibrio parahaemolyticus, Yersinia enterocolitica, Aeromonas hydrophila, Plesiomonas shigelloides, Campylobacter, Rotavirus, Calicivirus, Astrovirus and Adenovirus. Results Of the 603 cases, 260 (43.1%) were positive for bacteria or virus. Vibrio parahaemolyticus (10.9%) was the most prevalent bacteria identified, followed by Diarrheagenic Escherichia coli (8.1%), Aeromonas hydrophila (4.0%), and the overall detection rate of Shigella, Vibrio cholerae and Salmonella was only 3.0%. Calicivirus and Rotavirus were the common virus with detection rates of 8.6% and 7.1%, respectively. The total pathogen detection rate in winter (60.4%) was much higher than in other seasons (34.7%, 49.8% and 35.0% in spring, summer and autumn, respectively). Bacterial diarrhea occurred more frequently in summer and adults aged 19-60 years were affected mostly, while viral diarrhea mainly occurred in the winter and children aged 0-5 years were affected mostly. Conclusion The major pathogens to cause infectious diarrhea in Zhenhai were Vibrio parahaemolyticus, Diarrheagenic Escherichia coli, Aeromonas hydrophila, Calicivirus and Rotavirus. The surveillance and management of aquatic products should be strengthened to reduce the incidence of infectious diarrhea.