Vitamin A protects against development of infectious diseases, and B cells are important players in this process. Keys to the protective role of retinoic acid (RA) against infections appear to be its ability to enhance antibody responses against T-cell dependent and independent type 2 antigens, as well as to locally stimulate IgA production in mucosal tissues. The elucidation of molecular mechanisms involved in RA-mediated regulation of proliferation and differentiation of B cells not only helps us to understand how RA differentially regulates subsets of B cells, but might also lead to more targeted treatment of selected immune disorders and B cell malignancies.