AbstractWe report the case of a 62‐year‐old man who presented with shortness of breath, cough, bilateral lower limbs' swelling, and blackish discoloration of multiple fingertips over the past 2 months. Anti‐Ribonucleoprotein antibodies were found to be present, and gadolinium‐based cardiac MRI showed non‐vascular subendocardial enhancement with diffuse symmetrical thickening of the left ventricular wall. A diagnosis of Mixed connective tissue disease with secondary cardiac amyloidosis was thus made, and the patient was successfully managed with intravenous cyclophosphamide, corticosteroids, and other supportive measures. Although extremely rare, this case shows that secondary cardiac amyloidosis should be considered while managing patients with MCTD.