Hypoxia inducible factor 1alpha (HIF-1alpha) regulates the transcription of a number of genes under hypoxia and other extracellular or intracellular stimulations. It also promotes angiogenesis, tumor metastasis and invasion. To investigate the effect of hypoxia and reoxygenation on cell proliferation, invasion and adhesion, which are all related to ovarian cancer, we applied chemically-induced hypoxia in the cultured human ovarian carcinoma cell line, HO-8910PM. Semi-quantitative RT-PCR results show that CoCl2 induces the expression of HIF-1alpha in a time- and dose-dependent manner. MTT assay results show that CoCl2-induced hypoxia inhibits cell proliferation which is recovered by reoxygenation. The Boyden and cell adhesion test results indicate that CoCl2-induced hypoxia inhibits cell invasion and adhesion which are markedly enhanced by reoxygenation in the human ovarian carcinoma cell line, HO-8910PM. Collectively, our data provide insight into understanding molecular mechanisms of the invasiveness of ovarian cancer under the conditions of hypoxia and reoxygenation.