Immunocompromised patients are susceptible to many pathogens, including those that are predominantly problems in veterinary medicine. We report a case of a 42-yr-old white male who presented 19 months post-cadaveric renal transplant (for IgA nephropathy) with a 5 d history of nausea, vomiting, abdominal cramping and diarrhea. Admission chest X-ray revealed a suspicious mass lesion in the left lower lobe. Computed tomography (CT) guided biopsy of the lesion showed a large zone of CD68 +ve histiocytes in a non-caseating granuloma. Gram stain revealed multiple gram-positive rods within the histiocytes, which were eventually identified as R. equi. After 4 months of therapy with fluoroquinolones (Avelox) and Azithromycin a repeat CT showed complete resolution of the lesion. We reviewed the literature with special focus on the clinical features, challenges in diagnosis, and treatment of this rare infection (especially in the transplant patients who are also on immunosuppressive therapy).