The aim of this study was to observe the effectiveness of treatment with radical pinnectomy and investigate postoperative relapse cases in pinnal squamous cell carcinoma in cats. Twelve cats which were brought to surgery clinic of Istanbul University, Faculty of Veterinary Medicine were used. Biopsies were taken from the cases in which squamous cell carcinoma was suspected following anamnesis and the clinical examination of patients that were brought to our clinic. The patients were diagnosed on the basis of histopathological analysis of biopsy samples. Haemogram and biochemical blood analysis were performed and thoracic radiographs were taken as routine in cases that a decision was made to operate. After the area was prepared for operation radical pinnectomy or total external acoustic canal ablation along with radical pinnectomy were performed in the patients that were eligible for operation. Relapses seen in the postoperative period were re-operated with the techniques selected according to invasion status. Periodic controls of the patients were made after the operations and the cats were examined for relapse. In seven out of 12 cases, only squamous cell carcinoma; in three cases, actinic dermatitis actinic dermatitis in addition to squamous cell carcinoma, and in two cases, only actinic dermatitis lesions were detected. In the postoperative period, relapse was observed in the cases in which the squamous cell carcinoma lesion reached the lower half of the pinna or the external acoustic canal while relapse was not observed in cases with actinic dermatitis lesions or when the squamous cell carcinoma lesion was on the top part of the pinna. Relapse cases were re-operated using different operative techniques. It is concluded that performing radical pin­nectomy on actinic dermatitis lesions detected on the pinna before development into squamous cell carcinoma, and removing the tumour according to its localization with radical pinnectomy or total external acoustic canal ablation alongside radical pinnectomy is the most reliable treatment option in terms of relapse in cases of pinnal squamous cell carcinoma.