Rhodococcus equi (Corynebacterium equi) is able to produce infections not only in animals but also in patients, usually immunosuppressed ones. We report a new case of bacteremic pneumonia in a drug addict who was also infected by HIV. X-ray film of the chest showed a cavitated infiltrate in right upper lobe. R. equi was recovered from blood, respiratory secretions and lung tissue. The patient was with a prolonged course of antibiotics and also surgical treatment. In spite of both therapies, the patient died. We believe that this infection has to be considered in HIV infected patients with cavitated pneumonia and that early surgical treatment, combined with a prolonged course of multiple antibiotics, is advisable. Finally, in view of the severity of this infection, and its relation with other opportunistic infections, we believe that could be included as AIDS diagnostic criteria.