Despite many international conferences, there is no consensus on gestational diabetes mellitus and many groups only screen those women who present risk factors or who present during pregnancy complications attributable to this condition. Nevertheless, complications secondary to gestational diabetes are equally frequent whether the mother presents risk factor or not, and these risk factors are only present in 30 to 45% of gestational diabetes. Therefore, all pregnant women should be screened ... or none at all. The type of screening test to be used is just as controversial. The test proposed by the WHO alone allows screening and diagnosing simultaneously, but the cut-off value at 7.8 millimoles for post-charge glycemia seems to be too low for a pregnant woman, at the end of the second trimester. The real question of whether screening for and treating gestational diabetes will actually decrease perinatal morbidity and long-term complications for the mother and the infant cannot be answered as of yet. A large prospective study would be needed, including a control group that would not be treated despite pathological glucose levels, which is ethically inconceivable.