Prevalence and morphologic features of the apical delta in the canine teeth of dogs were determined to assist clinicians in the endodontic treatment of these teeth. Eighty-two canine teeth from mixed-breed dogs were cleared and dyed to outline root canal ramifications. Apical deltas were classified according to location in the dental arch, number of ramifications, and vertical extent of these ramifications from the apical terminus. A classification system was devised to aid in identification and treatment of the delta. Recommendations were made regarding indications for conventional and/or surgical endodontic therapy depending on the type of delta encountered. Apical deltas were detected in 69.5% of the canine teeth studied. Surgical endodontic intervention should be seriously considered when the delta is found to extend a distance > 1 mm from the apical terminus.