Background: Despite a general consensus about the importance of diagnosis and treatment of gestational diabetes mellitus (GDM), there is no agreement on screening criteria. The aim is to compare the performance of universal versus risk factor-based screening for GDM. Materials and Methods: The authors reviewed the medical records of 894 pregnant women, who were screened throughout 75 two-hour 75-gram oral glucose tolerance test (OGTT) between 24 and 28 weeks of gestation, from May 2012 to May 2014 at a single University Hospital. Each patient was evaluated for the presence of risk factors for GDM (age ≥ 35 years old, BMI ≥ 25 kg/m2, previous fetal macrosomia, a family history of type 2 diabetes mellitus, and high risk ethnicity). Results: Out of the 894 pregnant women, 150 (16.8%) were diagnosed with GDM according to the universal screening. Two hundred five women (22.9%) were at low risk for GDM, while 689 presented at least one or more risk factors. Using a risk factors based screening, 205 low-risk women would have skipped OGTT, but 19 of them (12.7% of women affected by GDM) received the diagnosis of GDM throughout OGTT. Nevertheless, risk factors showed a high strength as predictors of GDM diagnosis, with the exception of age ≥ 35 years. The comparison of maternal fetal outcomes between GDM women with or without risk factors presented no statistically significant differences. Conclusions: In the present authors' experience, the implementation of a risk factors based screening may lead to a reduction in the detection rate of GDM women.