B-cell activating factor of the TNF family is critical for the survival and maturation of B cells and play a role in the pathophysiology of chronic rhinosinusitis with nasal polyps (CRSwNP). In this study, nasal tissues were enrolled from 25 CRSwNP patients (asthmatic, 16; non-asthmatic, 9), 12 CRSsNP patients and ten control subjects, respectively. The immunoreactivity of BAFF, CD20 and CD138 were examined using immunohistochemistry staining. The mRNA expression of BAFF, CD20, eGLT, AID, GATA3 and CRTH2 were examined using real-time RTPCR. The protein levels of BAFF, IL-5 and IgE were measured using ELISA assays and the Unicap system, respectively. We found the numbers of BAFF+ cells, CD20? cells (B cells) and CD138+ cells (plasma cells) were significantly increased in polyp tissues compared with control groups. The concentrations of BAFF, IgE and IL-5 in tissue homogenates were also significantly increased in polyp tissues compared with control groups, and the BAFF protein level in the polyp homogenates was significantly associated with the IgE and IL-5 levels and with concomitant asthma in CRSwNP patients. Our findings indicate that BAFF expression is significantly increased in CRSwNP patients and may orchestrate inflammatory load in polyp tissues by regulating T and B cell-mediated response.