The discovery of endothelial progenitor cells has generated considerable interest in the field of vascular biology. These cells arise from a population of circulating mononuclear cells and have the capacity to form new blood vessels and contribute to vascular repair. Circulating endothelial progenitor cell numbers are reduced in patients with cardiovascular risk factors and in the presence of endothelial dysfunction, but are increased in response to ischaemia, oestrogens and drug therapy. They have been studied in pathologies from cardiovascular and renal disease to rheumatoid arthritis and pre-eclampsia. Pregnancy is a challenge to the maternal vascular system, requiring systemic adaptation and pronounced local changes in the uterus. Diseases of pregnancy such as pre-eclampsia and gestational diabetes increase the risk of pregnancy complications and are associated with endothelial dysfunction. We propose that endothelial progenitor cells have an important role in the regulation and maintenance of the vasculature during pregnancy. This review summarises our current understanding of endothelial progenitor cells, with specific reference to their role in angiogenesis and human pregnancy.