Objective of the Review: To systematise the information on MODY (Maturity-Onset Diabetes of the Young) during pregnancy. Key Points. MODY in pregnant patients should be distinguished from typical gestational diabetes mellitus, since these conditions require early pregnancy management. The article discusses combined criteria for differential diagnosis of types of diabetes mellitus in pregnancy and indications for molecular genetic testing. We describe clinical cases demonstrating the dependence of pregnancy outcomes on whether the foetus inherits the mutation or not. Also, the article describes the outlooks of non-invasive diagnosis of mutation status of the foetus and possible modification of therapy depending on the result. Conclusion. Diagnosis and therapy of MODY is a burning issue since there are no algorithms and the clinical experience is quite sparse. Keywords: MODY, gestational diabetes mellitus, GCK-MODY, HNF1A-MODY.