Introduction: In the Czech Republic, screening of glucose tolerance disorders is performed in all pregnant women in two stages: measuring glycaemia in a fasting patient within 14 weeks of pregnancy, and between the 24th and 28th weeks by performing an oral glucose tolerance test (oGTT). Goal: To determine how the oGTT is performed from the point of view of pregnant women. Materials and Methods: A total of 134 women in their 35th–44th week of pregnancy completed a non-standardized questionnaire. The research was carried out at workplaces in Zlín. Results: Only three respondents knew how many grams of glucose are drunk for an oGTT and one stated that it is necessary to fast for 8 hours before an oGTT. Capillary blood was taken in 22 cases, which is unacceptable in relation to recommendations. Conclusions: Inadequate knowledge concerning the preparation and performance of the oGTT may lead to distorted laboratory results.