This study was performed to evaluate full-mouth radiographic findings to determine the prevalence of dental abnormalities and analyze the relationship between dental abnormalities and age in small breed dogs. Sixteen predetermined categories of abnormal radiographic findings were evaluated in 233 small breed dogs. In total, 9,786 possible permanent teeth could be evaluated. Of those, 8,308 teeth were evaluated and abnormal radiographic findings were found in 2,458 teeth (29.6%). The most common teeth with abnormal radiographic findings were the mandibular first molars (74.5% on the left and 63.9% on the right) and the maxillary fourth premolars (40.5% on the left and 38.2% on the right). Bone loss of any type (15.8%) was the most commonly detected radiographic abnormal finding among the 16 categories. Dental conditions with a genetic predisposition were frequently occurred in the mandibular premolar teeth. Shih tzu frequently had unerupted teeth and dentigerous cysts. Among the teeth with abnormal radiographic findings, 4.5%, 19.8%, and 5.3% were considered incidental, additional, and important, respectively. Findings that were only detected on radiographs, which were not noted on routine oral examination, were more common in older dogs. Full-mouth radiographic evaluation should be performed to obtain important information for making accurate diagnoses.