We present four adult cases of acute renal failure associated with hypothyroidism. All patients presented with symptoms suggestive of moderate to severe hypothyroidism, such as cold intolerance, constipation, muscle weakness, and lower extremity oedema. Initial serum creatinine levels ranged between 115 and 203 micromol/L (1.3 and 2.3 mg/dL), with creatinine clearances (CrCl) ranging between 0.58 and 0.97 mL/s (34.5 and 58 mL/min). After 6-12 weeks of treatment with levothyroxin, serum creatinine levels decreased to the range of 80 and 124 micromol/L (0.9 and 1.4 mg/dL) and CrCl increased to 0.74-1.64 mL/s (44-98 mL/min). One patient had proteinuria of 800 mg/day, which decreased to the normal range (<200 mg/day) after levothyroxin treatment. One patient developed acute gouty arthritis before normalization of thyroid-stimulating hormone (TSH), which was successfully managed with prednisone therapy. All of our patients had increased creatine kinase (CK), ranging between 1000 and 2360 U/L (normal range, 22-165 U/L), which normalized after 6 weeks of levothyroxin treatment.