The clinical examinations that the physician should perform before the application of anesthesia are defined as preanesthetic evaluation. It is performed to determine the risk of anesthesia as a result of physical examination, laboratory tests and necessary consultations. It allows for the patient to be operated under optimum conditions as well as preventing the peroperative and postoperative complications that may occur. Although anesthetic drugs show their primary effects on the central nervous system, their secondary effects are seen on the respiratory and cardiovascular systems. It is very important to determine the diseases accompanying the patient's current condition by evaluating the respiratory system and cardiovascular system in the preanesthetic period. Thoracic radiography is a noninvasive auxiliary examination and diagnostic method that is frequently used in the preanesthetic period. It provides evaluation of extrathoracic structures, mediastinum, pleural cavity and pulmonary parenchyma. The material of this study consists of cats and dogs which came to Istanbul University-Cerrahpaşa, Faculty of Veterinary Medicine, Department of Surgery, Otorhinolaryngology Clinic and planned for elective surgery. Following anamnesis, physical examination, and laboratory investigations, thoracic X-Rays were taken from each patient in bilateral laterolateral (LL) and dorsoventral (DV) or ventrodorsal (VD) positions. By evaluating the results, in doubtful cases; additional tests such as positive contrast radiography, computed tomography, advanced cardiological examination were applied. As a result, in the light of the preanesthetic evaluation findings, the risk of anesthesia was determined and an anesthetic management suitable for the operation to be performed was planned.