The bacterium Bartonella henselae causes cat scratch disease, a self-limited zoonotic disease which is common among children and adolescents. The most typical clinical presentation is a regional lymphadenopathy that commonly involves only a single node of cervical and axillary lymph nodes. Inguinal localization is rarely described. We report a case of a 35-year-old Caucasian male complaining of a painless right inguinal mass and slight fever. A diagnosis of Bartonella henselae infection was made according to the histopathological exam of the excised mass, that showed an inflammatory state likely due to Bartonella, and to the titre of antibodies for this agent. Cat scratch disease can occur at any age and may also involve inguinal lymph nodes. Therefore it should always be included in the differential diagnosis of lymphadenopathy for adults. It is important that a meticulous personal history is obtained and that a specific serological test and pathological examination of the lesions are carried out. Often antibiotic treatment is not required because it is a benign disease and often resolves spontaneously.