Abstract: Objective To analyze the genetic characteristics of different serotypes of Vibrio parahaemolyticus (Vp) isolated from two food poisoning outbreaks. Methods The first outbreak occurred in the canteen of an electronic company in Shenzhen on May 17, 2010. About 20 people were infected. Nine anal swabs from patients and 3 suspicious food samples were collected. Twenty suspicious colonies were selected for each sample after culture. The second outbreak occurred in a catering center in Shenzhen on July 1, 2010. About 10 persons were infected. Seven anal swabs from patients, 2 suspicious food and 3 tray swabs samples were collected. Ten suspicious colonies were selected for each sample after culture. Each suspicious colony was identified using salt tolerance test, biochemical test, and serotyping. Different serotyping isolates were collected from both outbreaks, and characterized by tdh, trh, GS-PCR, orf 8 gene detection and pulsed field gel electrophoresis (PFGE) analysis. Results One hundred and eighty Vp isolates were collected from the first outbreak, of which, 107 isolates were serotype O3:K6,70 were O2:K28, 1 was O4:K34,1 was O3:K25,and 1 was O4:K12. Eighty Vp isolates were collected from the 2nd outbreak, of which, 44 isolates were serotype O3:K6, 10 were O4:K8, 10 was O11:K36, 10 was O11:K19 and 6 were O1:K56. All isolates of O3:K6, O1:K56, O4:K8, O11:K36 were positive for tdh, while negative for trh gene detection. The other isolates of O2:K28, O4:K12, O3:K25, O4:K34, and O11:K19 were negative for both genes. The isolates of O3:K6 and O11:K36 showed positive for both GS-PCR and orf 8 gene detection, while all the other isolates were negative for serotypes. PFGE analysis indicated that the PFGE pattern of 2 isolates (O2:K28) from patients were identical with 3 isolates (O2:K28) from food in the first outbreak, and 4 isolates (O3:K6) from patients were identical with 1 isolate (O3:K6) from egg tray swab in the second outbreak. PFGE patterns of isolates of O3:K6 from both outbreaks were identical. Vp isolates from the same sample with different serotypes were unrelated. Conclusion The first food poisoning outbreak was related to food contaminated by Vp and the second outbreak was related to egg tray contaminated by Vp. The serotyping and genetic data suggests that Vp with different serotypes from the same sample belong to different clonal complex, and are unrelated isolates in genetics.