BAKGROUND: Hyperglycemia in pregnancy is associated with significant maternal and perinatal morbidity and mortality. Early Identification and treatment of the hyperglycemia in pregnancy is the goal for improving maternal and fetal outcome. AIM: To determine the diagnostic performance of the 75g OGTT when done before the 24th week of pregnancy using the 75g OGTT done between 24-28 weeks as reference standard. METHODS: This was a cross-sectional study carried on between 1st of December 2016 to 30th May 2017 in Federal Teaching Hospital Ido-Ekiti and Ekiti State University Teaching Hospital Ado-Ekiti. 280 pregnant women who satisfy the study inclusion criteria were selected using convenience sampling method and were screened with the 75g OGTT before 24 weeks of Pregnancy. The women who tested negative at this stage were screened again between 24-28 gestational weeks of pregnancy. The diagnostic performance of the 75g OGTT and its FPG component were determined by measuring their sensitivity, specificity, positive and negative predictive power.