Cell Signaling Networks Database (CSNDB) is a data- and knowledge- base for signaling pathways of human cells. It compiles the information on biological molecules, sequences, structures, functions, and biological reactions which transfer the cellular signals. Signaling pathways are compiled as binary relationships of biomolecules and represented by graphs drawn automatically. CSNDB is constructed on ACEDB and inference engine CLIPS , and has a linkage to TRANSFAC. Our final goal is to make a computerized model for various biological phenomena. Any comments send to taka@nihs.go.jp.