Science and Education Publishing American Journal of Medical Case Reports 2374-216X 5 2 2017 3 7 Thyrotoxic Hypokalemic Periodic Paralysis 48 49 EN Zainab Jalal Asad Ullah Department of Internal Medicine, Conemaugh Memorial Medical Center, Johnstown, PA Ladan Mohammadi Jeanne Spencer AJMCR2017527 10.12691/ajmcr-5-2-7 2016 11 26 2017 1 6 2017 3 5 Thyrotoxic hypokalemic periodic paralysis (THPP) is a sporadic form of hypokalemic periodic paralysis (HPP), a rare disease which is manifested as painless muscle weakness in the presence of hyperthyroidism and hypokalemia. Our patient was recently diagnosed with hyperthyroidism due to Graves' disease and was started on antithyroid therapy. He presented few months later with upper and lower extremity weakness along with finding of hypokalemia in the background of hyperthyroidism. He was given potassium replacement therapy with resolution of symptoms.