Canine testicular tumours frequently occur and share relevant features with their human counterparts, thus being a putative model in comparative oncology. The authors present data on canine testicular tumours submitted to the Istituto G. Caporale over the last 12 years. In total, 183 testicular neoplasms were diagnosed: 108 seminomas, 37 Sertoli cell tumours, 18 interstitial Leydig cell tumours, 10 mixed tumours, 9 other primary tumours and one metastatic neoplasm. A systematic and more detailed collection of data (signalling, history, clinical signs and follow-up) enables a better evaluation of clinical and biological features of animal tumours, as well as a clear assessment of the real impact, if any, of specific intrinsic and extrinsic risk factors.