Myocardial calcification is a known late complication of end-stage renal disease, while myocardial calcification in acute kidney injury is rare and usually associated with obvious myocardial injury. This paper de scribes a patient with emphysematous pyelonephritis and acute kidney injury. There was no significant myocardial injury. The patient developed marked hyperphosphatemia due to acute kidney injury and massive tissue injury despite of phosphate binders and intermittent hemodialysis being administered. She had hypocalcemia initially but developed hypercalcemia subsequently. Rapid development and progression of myocardial calcification were documented by computed tomography. This paper discusses possible cause s of the rapid onset of myocardial calcification, the adequacy of dialysis, and administration of phosphate binders in hyperphosphatemia and acute kidney injury. Cautions to avoid development of extraosseous calcification are needed even in the setting of acute kidney injury.