We report the first case of aortic and mitral Haemophilus paraphrophilus endocarditis complicated by abscess of the aortic annulus in a 30-year old man with post-rheumatic mitral regurgitation. We recall the peculiar clinical features and course of this bacterial endocarditis of uncommon origin. We insist, in particular, on the occurrence of cerebral embolism and on the two-dimensional echocardiographic diagnosis of an aortic annulus abscess confirmed at surgery. Cure was obtained by aortic and mitral valve replacement and by the prolonged antibiotic therapy made necessary by the presence of cerebral lesions. After 3 months, there were no neurological sequelae, but doppler-echocardiography showed a persistent washed out pouch the reports of which with the surrounding structures were determined by transoesophageal echocardiography: moderate aortic regurgitation was detected at that level.