A 5-month-old female infant who had chronic diarrhea and acute renal failure was referred to Chulalongkorn Hospital for further investigation and management. Laboratory investigation revealed elevated blood urea nitrogen and creatinine level, hypocalcemia, hyperphosphatemia, and hyponatremia. Ultrasonography of the kidneys showed normal size with bilateral hyperechoic kidneys. Eyes examination was compatible with oxalosis maculopathy. Urine organic acid analysis revealed peak of oxalate and glycolate. Clinical impression concluded acute renal failure from hyperoxaluria. The patient underwent continuous venovenous hemodiafiltration (CVVH-DF) with regional citrate anticoagulation and expired on day 13 after admission. Pathological examination of kidney necropsy revealed diffuse intraluminal deposition of oxalate crystals within the renal parenchyma. Primary hyperoxaluria is a very rare disease and has rarely been reported in Thailand. In the presented case, the diagnosis was delayed due to uncommon presentation and unavailability of diagnostic laboratory.