OBJECTIVE To determine the apical anatomy of canine teeth in cats. METHODS 70 permanent canine teeth of cats. METHODS The teeth were extracted, cleaned, and radiographed, and the root canals were stained with India ink, then cleared in methyl salicylate. The apical root canal anatomy was studied by examining dental radiographs and microscopic measurements performed on the cleared specimens. RESULTS Apical root canal anatomy in cats has the same "sprinkler-rose" appearance as seen in dogs. The mean length of the radiodense apex on radiographs was 2.8 +/- 1.2 mm. The mean lengths of the apical ramifications were 1.9 +/- 0.4 and 1.6 +/- 0.4 mm for upper and lower canine teeth, respectively; mean numbers of apical ramifications were 13 +/- 6 and 12 +/- 5, respectively; and mean ratios (length of ramifications/length of root) were 0.16 +/- 0.03 and 0.15 +/- 0.04, respectively. There was significant (P < 0.05) difference in the length of apical ramifications between upper and lower canine teeth and significant (P < 0.05) positive correlation between the length of the root and the length of apical ramifications for all canine teeth. CONCLUSIONS Primary apical foramen is not present in mature canine teeth of cats. CONCLUSIONS There is little risk of apical penetration by files during endodontic therapy of canine teeth of cats; however, the multiple foramina require that apical instrumentation is thorough to prevent soft tissue remnants causing failure of the procedure.