This study examined the effects of hepatocyte growth factor/scatter factor (HGF/SF) on the adhesion of HT115 (human colon) and MDA MB 231 (human breast) tumour cells to an extracellular matrix, Matrigel, together with the tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin. Treatment of cells with HGF increased cell adhesion to matrix. Following adhesion to Matrigel, FAK and paxillin were quickly phosphorylated and located to the focal adhesion area. HGF/SF increased both tyrosine phosphorylation of FAK and paxillin and also increased formation of focal adhesion. HGF also induced an increased spreading on matrix. It is concluded therefore that HGF/SF stimulated FAK and paxillin phosphorylation resulting in an increased tumour-matrix adhesion.