Dendritic cells (DC) attract both T and B lymphocytes to induce an efficient antigen‐specific immune response. Recently, it was shown that naïve T cells are attracted to DC by dendritic cell chemokine 1 (DC‐CK1, CCL18). The potent B lymphocyte chemoattractant BLC (CXCL13) was previously shown to be essential for homing of lymphocytes into secondary lymphoid organs and for the development of B cell follicles. As the cells that produce BLC are largely unknown and BLC could be a candidate chemokine for the recruitment of B cells to DC, we analyzed different DC subsets for expression of BLC. Here we demonstrate that monocyte‐derived DC as well as activated blood DC indeed express and secrete BLC. Interestingly, ligation of the CD40 molecule down‐regulated BLC expression in monocyte‐derived DC. Staining of tonsilar sections indicated that BLC is expressed by follicular dendritic cells and germinal center dendritic cells (GCDC) in vivo. Real‐time quantitative PCR confirmed the expression of BLC in isolated GCDC. Since both B cells and activated T cells express the receptor for BLC, our findings implicate an important role for BLC in establishing the interaction of DC with T cells and B cells. Furthermore, CD40/CD40 ligand interactions could modulate this process by down‐regulating the expression of BLC.