The objective of this study is to assess the diagnostic accuracy of CHOKAI, STONE and STONE plus scores in detecting ureteral stones larger than 5 mm. This comparative diagnostic accuracy study was performed in a tertiary care emergency department (ED) and included consecutive patients who presented to the ED with flank pain and underwent ultrasonography and CT over a 1-year period. The performance of these scoring scales in detecting >5 mm ureteral stones was determined by area under the receiver operating characteristics (AUROC) comparison. Ureteral stones were detected in 270 (70.3%) of 384 patients included in the study. While 146 patients (54.1%) had <5mm ureteral stones, 124 patients (54.1%) had stones of 5mm or more in size. The performance of the CHOKAI score in predicting ureteral stones (AUROC 0.903 [95% CI 0.869-0.931]) was superior to the STONE PLUS score (AUROC 0. 879 [95% CI 0.842-0.910]) (p<0.001); STONE PLUS score was also superior to STONE score (AUROC 0.767 [95% CI 0.722-0.809]) (p<0.001). STONE score did not show a statistically significant difference between large and small stone groups (p=0.064). Analysis of the diagnostic value of CHOKAI score (AUROC 0.731 [95% CI 0.684-0.775]) and STONE PLUS scores (AUROC 0.725 [95% CI 0.678-0.769]) in predicting >5 mm stones showed no statistically significant difference (p=0.59). CHOKAI and STONE PLUS scores are useful in predicting >5 mm ureteral stones and have similar diagnostic utility to each other. STONE score does not provide accurate diagnostic information about ureteral stones larger than 5 millimeters.