The purpose of this study was to determine the diagnostic utility of helical computed tomography (CT) for the diagnosis of ectopic ureters in the dog and to compare these findings with those of digital fluoroscopic excretory urography and digital fluoroscopic urethrography. Ureteral ectopia was confirmed or disproved based on findings from cystoscopy and exploratory surgery or postmortem examination. Of 24 dogs (20 female, 4 male) evaluated, 17 had ureteral ectopia. Digital fluoroscopic excretory urography and CT correctly identified ureteral ectopic status and site of ureteral ectopia (P < .05). Urethrography did not reliably detect ureteral ectopia. No false-positive diagnoses of ureteral ectopia were made in any of the imaging studies. Cystoscopic findings significantly agreed with findings during surgery in determining ureteral ectopic status and ectopic ureter site. One false-positive cystoscopic diagnosis of unilateral ureteral ectopia was made in a male dog. Kappa statistics showed better agreement between CT and both cystoscopy and surgical or postmortem examination findings with regard to presence and site of ureteral ectopia compared with other imaging techniques. CT was more useful than other established diagnostic imaging techniques for diagnosing canine ureteral ectopia.