An in vitro migration and invasion assay was used as the model system to study the effect of 3T3 fibroblast conditioned medium (FCM) and purified human fibronectin on the invasion of cervical carcinoma cells. The 3T3 FCM significantly enhanced both the migration and the invasion of a cervical carcinoma cell line, HeLa. This enhancement of migration and invasion was inhibited by anti-fibronectin antibody. Purified fibronectin alone enhanced the invasion in a dose-dependent manner for all cervical carcinoma cell lines, HeLa, CAC-1 and TMCC. The pretreatment of cells with cell binding aminosequences, GRGDSP and/or YIGSR blocked the enhancement of cell invasion. The implication of these findings for the invasion of cervical carcinoma is discussed.