Dilated cardiomyopathy (DCMP) is a serious and rare complication of unknown chronic hypocalcaemia. We report three cases of asymptomatic chronic hypoparathyroidism post thyroidectomy complicated of DCMP with heart failure. The first case is 56-year-old patient, asymptomatic for 14 years, admitted for generalized seizures of sudden onset revealing hypoparathyroidism, on examination we found diastolic murmur at mitral focus with signs of hypocalcaemia confirmed by biology: Serum calcium at 40 mg/L, serum phosphate at 98mg/L, her brain scan showed a Fahr syndrome and her transthoracic echocardiography (TTE) showed a DCMP, global hypokinesia and an ejection fraction at 39%. The second is 29-year-old patient admitted for insidious hypoparathyroidism dating back to 8 years, On blood examination she had hypocalcaemia at 32 mg/l with PTH level at 10.5 pg/ml, her TTE showed DCMP, global hypokinesia and an ejection fraction at 28%. The third case is a 62-year-old patient who had thyroidectomy 5 years ago, admitted for etiological assessment of DCMP revealed by dyspnea, his blood examination showed hypocalcemia at 50mg/l, phosphoremia at 109 mg/l, his TTE objectified DCMP with ejection fraction at 20%. DCMP is a very serious complication of hypoparathyroidism after cervical surgery. Hence, the importance of the systematic screening based on calcium levels after any thyroid surgery and adequate supplementation.