With the recent discovery and cloning of the lipopolysaccharide-binding protein (LBP), the "adapter-molecule" for LPS-binding to the cell surface receptor CD14 was found. The ligand-receptor pair LPS/LBP-CD14 seems to be one important element in LPS-mediated activation of monocytic cells and possibly granulocytes and B cells. Here, some of the known functions of the proteins involved, LBP and CD14, are reviewed in the context of other endotoxin recognition studies, and the outlook for ongoing and future investigations is described.