The 50-gram non-fasting one hour Glucose Challenge Test (GCT) is today the one most widely implemented as a screening test for Gestational Diabetes Mellitus (GDM). Positive result of GCT creates a preliminary GDM diagnosis. Diagnosis of GDM labels a pregnancy high risk. Any highrisk pregnancy can cause maternal anxiety. The aim of the study was to investigate pretest and posttest anxiety levels in pregnant women undergoing GCT. Anxiety levels were evaluated by Hamilton Rating Scale for Anxiety (HAMA score). Pretest HAMA score was 7.1±3.34 in the women with preliminary GDM diagnosis, and 6.69±5.51 in the women with negative GCT results. After delivering GCT results, HAMA score was 8.64 ± 8.10 in the women with preliminary GDM diagnosis and 4.29±2.29 in the women without preliminary GDM diagnosis. Pretest levels of anxiety among all pregnant women undergoing GCT were increased. However, this was temporary in women with negative GCT, whose anxiety levels decreased after delivering GCT results. Among women preliminary diagnosed with GDM, posttest HAMA evaluation revealed sustained increased levels of anxiety. Concerns regarding the anxiety caused by screening for GDM were confirmed by the results of our study