Pneumothorax is the accumulation of air in the extrapulmonary space between the pleura and the chest wall. Spontaneous pneumothorax can present with various electrocardiographic (ECG) findings including axis deviation, bundle branch block and T waves inversion. A 23-year-old young male patient of slim build presented to the accident and emergency department with sudden-onset chest pain and shortness of breath. He had pleuritic chest pain, worse on breathing. Electrocardiogram showed right axis deviation, diminished or low-amplitude R waves and small-amplitude QRS complexes in the precordial leads. Vital signs were stable and physical examination showed reduced air entry on the left side. Chest radiography showed significant left-sided pneumothorax and the patient had an emergency chest drain inserted. ECG changes resolved with the resolution of pneumothorax. He was discharged home after four days of hospital admission and complete resolution of pneumothorax.