Introduction: Cardiobacterium hominis and Cardiobacterium valvarum are well known, though rare, etiologic agents of infective endocarditis. Cardiac devices are increasingly implanted. Case Reports: Two cases of infective episodes in pacemaker (PM) treated patients with respectively C. hominis and C. valvarum are presented. In one case blood-culture bottles yielded growth of C. hominis at two episodes with two years apart. At the second episode a vegetation was recognized at the PM lead and the PM device and lead was removed. In the C. valvarum case, echocardiography revealed a bicuspid aortic valve with severe regurgitation and a more than 1 cm sized vegetation. Conclusion: The cases illustrate the diversity in disease severity by Cardiobacterium species. Careful follow up has to be performed in order not to overlook a relatively silent relapsing infection.