Introduction: Rhodococcus equi is a gram positive coccoid rod that causes pulmonary infections in immunosuppressed patients. Methods: We retrospectively analyzed epidemiological, clinical, microbiological, radiological, and immunological features as well as the outcomes of 13 AIDS patients with R. equi infection. Results: Between January 1994 and December 2012, 13 patients attending the AIDS department of the Infectious Diseases reference hospital in Buenos Aires were diagnosed with R. equi infection. All were men, the median age was 27 years. At the time of diagnosis, the median of CD4+ T cell counts was 11 cells/mu l. Twelve patients presented pulmonary disease with isolation of the microorganism from sputum or bronchoalveolar lavage; in the other patient the diagnosis was postmortem with positive culture of cerebrospinal fluid. The most frequent clinical manifestations were fever, haemoptysis, and weight loss. The predominant radiological finding was lobe consolidation with cavitation. Nine patients died after a median survival of 5.5 months. In all of them, cultures persisted positive until the last admission. The other 4 patients did continue clinical follow-ups. Conclusion: The insidious course of R. equi disease and the difficulties in the isolation of the microorganism contribute to the delay in the diagnosis and to the high mortality rate of this opportunistic infection.