The HACEK microorganisms (Haemophilus spp, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae) account for 3% of the cases of endocarditis. They have the following similar clinical and microbiological properties: are Gram-negative bacilli, more easily isolated in aerobic media; their cultures require prolonged incubation time for growing (mean, 3.3 days); and may be considered part of normal flora of upper respiratory tract and oropharynx. The following characteristics have been identified in endocarditis caused by the HACEK microorganisms: insidious clinical findings; difficult diagnosis due to the fastidious nature of the microorganisms; and negative cultures. The Eikenella corrodens endocarditis was first described in 1972. That microorganism continues to be a rare etiological agent. We report the case of a female patient with native valve, who had Eikenella corrodens infective endocarditis.