Gestational diabetes mellitus (GDM) is a common complication of pregnancy In the course of pregnancy elevated levels of hormones and other proteins having insulin-antagonistic effects lead to higher insulin resistance in peripheral tissues, followed by hyperinsulinemia. Risk factors for the development of GDM have been well-established. However, the debate whether polycystic ovary syndrome (PCOS) may predispose to GDM continues. Patients with PCOS are often affected by obesity dyslipidemia, hyperinsulinemia, and tissue-specific insulin resistance. Obesity occurs in 50% of the cases, while tissue-specific insulin resistance is observed in 20-40% of the affected patients. This paper aims at systematizing risk factors that could contribute to the development of GDM, as well as reviewing literature reports and analyses on the occurrence of a potential correlation.