Background. In the search for possible "candidate" for the role of a key regulator of the paracrine relationship of endocrinocytes of pancreatic islets, which involved both in physiological and pathological processes, we paid attention to the system of nitrogen monoxide (NO). The interest of its study was due to the fact that a wide range of general biological actions of NO includes not only regulatory and protective effect, but also a range of pathological reactions. The aim of our study was to examine the pattern of expression of endothelial, neuronal and inducible NO-synthases in pancreatic islets in offspring of female rats with experimental gestational diabetes (EGD) at age 3 months of (prepubertal period). Materials and methods. Study was carried out on 10 male rats the off springs of females with normal pregnancy and 10 male rats the off springs of females with EGD. To analyze the system of nitrogen monoxide in histological sections of pancreatic islets we examined the expression of neuronal, inducible and endothelial isoforms of nitric oxide. The study has found that in control rats the largest area of enzyme was typical for endothelial isoform, while the content of immunoreactive material was the largest for inducible one. The chronic fetal hyperglycemia leads to a change of the features of expression of isoforms and characterized by increased content of nNOS and increased area of iNOS and the most increased values of content and area of eNOS compared with all other isoforms’ expression figures. Conclusion. We believe that a violation of homeostasis of glucose in the fetus during the last trimester of pregnancy alters the expression patterns of NOS isoforms in pancreatic islets, which probably can be a cause of diabetes in adulthood.