A 42-year-old man with a history of Billroth II-gastrectomy, chronic alcoholism, and malnutrition developed acute tetraparesis, two days before admission. He presented with bilateral, proximal upper and lower limb weakness, limb girdle wasting, bilaterally reduced Achilles tendon reflexes, and bilateral stocking-type sensory disturbances. Laboratory data revealed hypokalemia (2.2 mmol/L), elevated creatine kinase (7282 U/L), metabolic alkalosis and reduced urine potassium, albumin, and total protein. Muscle biopsy showed atrophic, necrotic, and regenerating fibers, endomysial macrophages, and vacuolar degeneration, interpreted as hypokalemic myopathy. With the correction of the serum potassium, tetraparesis rapidly resolved. With other causes excluded, malnutrition and gastrectomy were considered responsible for hypokalemia in this patient with acute tetraparesis and chronic alcoholism.