Acute flaccid quadriparesis secondary to hyperkalemia is a very rare and serious but reversible medical emergency. We present a case of a 73-year-old female who was admitted with rapidly progressive ascending paraparesis progressing to quadriparesis in about 10 h due to hyperkalemia. Patient was treated with antihyperkalemic measures. Her power improved dramatically as potassium levels normalized and she had an uneventful recovery.