Hypoxia-oxygen deficiency is a feature of most solid malignant tumours. This leads to the selection of an aggressive neoplasm phenotype by activating molecular factors including hypoxia inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF) promoting angiogenesis, and also by the influence of the tumour microenvironment, no possibility of fixation of DNA damage after radio- and chemotherapy, and the change in cadherin activity. Another mechanism of hypoxia facilitates the survival, and activity of cancer stem cells (CSCs). The described therapies eliminating hypoxia include the use of cytotoxins, anaerobic bacteria, YC-1 factor, arsenic trioxide (As2O3), and eradication of CSCs by using retinoic and ursolic acid. The paper describes hypoxia as the cause of failure in the treatment of gynaecological cancers and therapies eliminating it.