Acute phosphate nephropathy is a form of acute kidney injury (AKI) due to oral sodium phosphate (ONaP) purgatives used for bowel cleansing before colonoscopy. Usually, 45 ml ONaP is given two times daily 12-24 hours prior to colonoscopy. Intestinal absorption is followed by transient hypocalcemia and hyperphosphatemia in almost all patients. In addition, severe hyperphosphatemia, symptomatic hypocalcemia, hypernatremia, hypocalcemia, hyponatremia, hypokalemia, high anion gap metabolic acidosis and AKI can be seen. The patient presented in this paper is a 65-year-old female. She was diagnosed with type 2 diabetes mellitus and hypertension. Colonoscopy was performed in order to investigate the etiology of iron deficiency anemia. ONaP was administered for preparation of colonoscopy and AKI which was clinically compatible with APN developed after the procedure.