[en] The oral glucose tolerance test (OGTT) has been widely used for the diagnosis of diabetes mellitus, gestational diabetes or impaired glucose tolerance. However, since 1997, OGTT is not considered anymore as the first choice test for the diagnosis of diabetes mellitus or impaired glucose tolerance, being replaced by fasting glycaemia. Numerous studies, however, stressed the discrepancies between these two diagnostic approaches, so that OGTT still has defenders as a useful tool to diagnose diabetes. Besides, emphasis has been recently put on both postprandial hyperglycaemia, considered as a major cardiovascular risk factor, and impaired glucose tolerance as a predictor of progression toward overt type 2 diabetes, two parameters well addressed by the OGTT. Thus, even if the place to be reserved to the OGTT is controversial, in our opinion, this test still has a place in clinical biology.