OBJECTIVE: To describe a method for radiographic measurement of the mechanical joint angles of the tibia in the sagittal plane and report reference ranges for a population of dogs with cranial cruciate ligament disease, and specifically for Labrador Retrievers. STUDY DESIGN: Retrospective evaluation of radiographs. ANIMALS: Canine tibia (n=150) of dogs evaluated for cranial cruciate ligament disease; 104 tibiae were from Labrador Retrievers, 46 tibiae were from other medium- to large-breed dogs. METHODS: Medial-lateral radiographs were used to establish anatomic landmarks and measure the mechanical cranial distal tibial angle (mCrDTA) and mechanical caudal proximal tibial angle (mCaPTA). RESULTS: For all tibiae mean mCrDTA was 81.6 degrees and mCaPTA, 63.6 degrees . For Labrador Retriever tibiae mean mCrDTA was 81.7 degrees and mCaPTA, 63.8 degrees . For non-Labradors, means mCrDTA was 81.5 degrees and mCaPTA, 63 degrees . Labrador Retrievers were significantly younger than non-Labradors in our study population. No significant differences were noted between Labrador Retrievers and non-Labradors for mCrDTA or mCaPTA and correlations between mCrDTA and mCaPTA were neither strong nor significant. CONCLUSION: A method was established for radiographic measurement of mechanical joint angles of the canine tibia in the sagittal plane. Reference ranges are reported for a population of Labrador Retrievers and a population of non-Labradors with cranial cruciate ligament disease. CLINICAL RELEVANCE: Measurement method and reference ranges provided for mechanical tibial angles may be used to aid in diagnosis, surgical planning, and postoperative critique for hindlimb angular deformities.