The high prevalence of preterm delivery (PTD) (7,2 to 8,4% in Poland) may suggest that much more attention should be paid to the early detection, as well as prevention, of this condition. Spontaneous preterm birth is a multifactoral disease, with possible genetic and environmental determining factors. Genes of cytokines modulating the immunological answer, genes of metalloproteinases and genes of coagulation cascade and fibrinolysis may have a significant involvement in the development of PTD. Population studies conducted so far comprise exact, individual evaluation of risk factors in women with tendency to PTD and have indicated a genetic susceptibility to PTD occurrence. Another direction of research is the investigation of candidate genes which are directly or indirectly involved in the biochemical pathways related to the disease. Current studies allow to define several candidate genes predisposing to PTD. The next step is the family molecular analysis of candidate gene polymorphisms both: in women with burdened anamnesis and first and second degree relatives (mothers, grandmothers, sisters). Numerous studies, besides the individual genetic predisposition, focus on the possible gene-environmental interactions and their role in the development of PTD. In this manuscript we have summarized the current researches of genetic basis of preterm delivery.