Objectives: to investigate the effect of tumor – stromal cell interaction on the behavior of oral human squamous carcinoma cell line-5 (HSC-5). The activation of MMP-2, which was implicated in tumor invasion and metastasis processes, was determined along with the abilities of cell invasion and migration. Methods: 24-hour human gingival fibroblast conditioned medium was used to stimulate HSC-5 for 48 hours. MMP-2 activation was analysed from the cultured medium by zymography. RNA was extracted for the analysis of MT1-MMP, TIMP-1 and TIMP-2 by RT-PCR. Cell spreading and invasion were performed in the model of type I collagen gel for 48 hours and analysed by H&E stained paraffin sectioning. Results: The activation of MMP-2 was observed concomitant with the increase of the expressions of MT1-MMP and TIMP-2, the main component of MMP-2 activation machinery, without the change of TIMP-1. When grown on type I collagen gel, HSC-5 formed a cord-like structure. However, in the presence of human gingival fibroblast conditioned medium, cells spreaded throughout the surface of collagen gel. Conclusions: Influence of normal human gingival fibroblasts secretion was effected on the invasiveness of the oral human squamous carcinoma cell line-5 (HSC-5) by increasing MMP-2 activation and cell migration on type I collagen.