We report the case of a 42 years woman known to have a cardiac heart failure attributed to restrictive cardiomyopathy for want of any other plausible diagnosis. Evolution and repeted investigations finally permitted to rectify the diagnosis by revealing a constrictive pericarditis, remained occult 9 years during. The differentiation of restrictive cardiomyopathy and constrictive pericarditis has been a perennial problem in clinical cardiology. Diagnosis of constrictive pericarditis is based on associated signs sometimes too poor to go straight to thoracotomy. We discuss the mean to approach more precisely this uncommon pattern named occult constrictive pericarditis.