O besity is defined by the World Health Organization as a body mass index (BMI) of ≥30 kg/m 2. [1] When the BMI is ≥40 kg m 2 , the patient enters the class of extreme obesity (Class III). Many pathological changes occur; obesity negatively affects all organ systems, led by the respiratory system (obstructive sleep apnea, obesityhypoventilation syndrome, bronchial asthma, pulmonary hypertension), the cardiovascular system (arrhythmia, atherosclerosis, heart failure, coronary artery disease, peripheral vein disease, sudden cardiac death, systemic hypertension, thromboembolism), and the endocrinemetabolic system (diabetes mellitus, hyperinsulinemia, hypothyroidism, insulin resistance, metabolic syndrome). [2] These pathological changes make the management of both general anesthesia and regional anesthesia more difficult in obese patients. In particular, the use of anatomical landmarks to guide the administration of regional anesthesia in the traditional method can become extremely difficult and may lead to failure in this patient population. As a result, in recent years, performing the procedure with ultrasound (US) guidance, a non-invasive method without negative effects, such as radiation, has become popular. This case report describes the administration of spinal anesthesia in an obese patient with the assistance of US due to pulmonary issues.