Innate immunity is the first line of defense by a host against invading pathogens. Several signaling pathways participate in the immune response, one of which is the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. Various evidences have been provided to suggest that the JAK/STAT pathway is involved in both antibacterial and antiviral immunities. In this study, the full-length cDNA and gene sequence of STAT (designated as FcSTAT) was cloned from the Chinese white shrimp, Fenneropenaeus chinensis. Phylogenetic analysis reveals that the FcSTAT is clustered with STAT5s and STAT6s from vertebrates and STATs from invertebrates. Quantitative real-time PCR exhibited that the FcSTAT had a wide distribution in all detected tissues and developmental stages. Time course analysis of the transcription level after WSSV challenge showed a noticeably early up-regulation of FcSTAT in hemocytes, hepatopancreas, and intestines. The expression levels of FcSTAT increased corresponding to Vibrio anguillarum stimulation in both hemocytes and hepatopancreas as well. All these imply that the JAK/STAT pathway participates in the immune response against bacteria and virus in F. chinensis.