We prepared a specific antagonist for hepatocyte growth factor (HGF) and designated it HGF/NK4. HGF/NK4 is composed of N-terminal 447 amino acids of the alpha-chain of HGF, thus contains the N-terminal hairpin domain and subsequent four kringle domains. HGF/NK4 competitively inhibited the specific binding of HGF to the receptor. Importantly, HGF/NK4 neither stimulated DNA synthesis of primary cultured rat hepatocytes (mitogenesis) nor induced cell scattering (motogenesis) and branching tubulogenesis (morphogenesis) of MDCK renal epithelial cells, however, HGF/NK4 almost completely inhibited the mitogenic, motogenic, and morphogenic activities of HGF. HGF/NK4 also suppressed tyrosine phosphorylation of the c-Met/HGF receptor induced by HGF. Apparently this is the first documentation of a specific antagonist which abrogates the mitogenic, motogenic, and morphogenic activities of HGF.