Constrictive and effusive-constrictive pericarditis are rare cardiac disorders. Only rarely are the conditions caused by purulent infection, and even more infrequently by anaerobe bacteria. We describe a case of constrictive - and effusive-constrictive pericarditis due to Cutibacterium (formerly Propionibacterium) acnes in a 75-year old, immunocompetent and previously healthy patient without any predisposition. The patient was successfully treated with subtotal pericardiectomy and beta-lactam antibacterials. C. acnes was the only infectious agent recovered from samples of cultured pericardial tissue. C. acnes is a microaerophilic, Gram-positive anaerobic bacillus that is a part of the normal flora. In symptomatic patients, however, positive samples should be considered as clinically relevant and not dismissed as contamination. Due to the low virulence, the capability of adherence and biofilm formation of C. acnes, diagnosing C. acnes constrictive pericarditis may be difficult. In the context of compatible symptoms, the incubation time of clinical samples should be prolonged or supplemented by polymerase chain reaction techniques. Parenteral beta-lactam antibacterials are considered the drugs of choice. Severe constrictive and effusive-constrictive pericarditis caused by C. acnes is rare, but can be seen even in otherwise healthy patients. Prolonged incubation time and polymerase chain reaction techniques may be required in order to confirm diagnosis.