Summary. The numerous studies on the multifunctional nature of the nitric oxide (NO) have suggested the wide variety of functions mediated by this molecule in vital processes in cardiovascular, nervous, gastrointestinal, urogenital system and during immunological reactions. In this review we present the results of experiments carried out on animal models, as well as the results of clinical studies considering the role of NO and its metabolites during pregnancy and delivery. During pregnancy NO is one of the most important relaxing factors of myometrium, and also no less important in the control of blood flow in uterus and placenta. Changes in NO production at the end of pregnancy could be important for the beginning of delivery and cervical maturation. Also it seems, and our preliminary results as well as results of other investigators suggest, that higher levels of NO are produced during some pathological conditions in pregnant women, e.g. IUGR, preeclampsia, preterm delivery. The implica- tions of NO donors or inhibitors of NO synthesis used in therapy of previously mentioned conditions will be also discussed.