The aim of this study was to examine the effects of fibroblast growth factor-2 (FGF-2) on cancer cell invasion and on fibroblast proliferation in an in vitro model of invasion. Three kinds of human oral squamous cell carcinoma cell lines with different invasive activity were used: OSC-20, OSC-19 (lower invasive type), and HOC313 (higher invasive type). FGF-2 and its high-affinity receptors FGFR-1 and FGFR-2 were detected by western blotting. The expression of FGF-2 and FGFRs mRNA was examined in cultured human oral squamous cell carcinoma cells by reverse transcriptase polymerase chain reaction (RT-PCR). Furthermore, recombinant human FGF-2 (rhFGF-2) was reacted with each cell line, and the invasion rate was determined by invasion assay. We also observed the behavior of cancer cell invasion in the collagen gel invasion model in the presence or absence of FGF-2-neutralizing antibody (anti-FGF-2). HOC313 cells showed higher expression of FGF-2 than OSC-20 and OSC-19 cells. The addition of rhFGF-2 promoted not only the proliferation of fibroblasts, but also the invasion of all cancer cell lines. In contrast, the addition of anti-FGF-2 completely inhibited the invasion of OSC-20 and OSC-19 cells. These results suggest that a higher invasiveness of squamous carcinoma cells is associated with higher production of FGF-2, which acts in an autocrine fashion to promote cancer cell invasion, and in a paracrine fashion to promote fibroblast proliferation.