Abstract: Autotaxin (ATX) is a prometastatic enzyme initially isolated from the conditioned media of human melanoma cells that stimulates a myriad of biological activities including angiogenesis and the promotion of cell growth, survival, and differentiation through the production of lysophosphatidic acid (LPA). ATX increases the aggressiveness and invasiveness of transformed cells, and ATX levels directly correlate with tumor stage and grade in several human malignancies. To study the role of ATX in the pathogenesis of malignant melanoma, we developed antibodies and small molecule inhibitors against recombinant human protein. Immunohistochemistry of paraffin embedded human tissue demonstrates that ATX levels are markedly increased in human primary and metastatic melanoma relative to benign nevi. Chemical screens identified several small molecule inhibitors with binding constants ranging from nanomolar to low micromolar.