GDM is the most common metabolic condition experienced in pregnancy. Prevalence rates continue to increase in parallel with rising obesity rates, type 2 diabetes rates in the background population and rising maternal age. GDM is associated with adverse maternal health for both the mother and her infant. In addition GDM is associated with future cardio-metabolic risk for the mother and diabetes and obesity in the offspring in later life. Despite the wealth of knowledge about GDM its treatment and outcome, debate still continues on its screening. The world is united that women should be screened at 24-28 weeks and the recommended test is an oral glucose tolerance test (OGTT). Debate continues on the cut off values for diagnosis on the OGTT and the associated glucose load. The talk will focus on the most commonly used criteria, the evidence related to them and the associated outcomes. In addition researchers are exploring other biomarkers that have potential to replace the OGTT that is burdensome for the woman and the health professional which will be explored.