Legionnaires disease is primarily a pneumonic illness with possible multisystem involvement. Major risk factors include immunodeficiency, smoking, alcoholism and chronic obstructive pulmonary disease among others. We report a peculiar case of Legionnaires disease presenting with diarrhea as the chief complaint and no respiratory symptoms throughout the course of disease. The patient had no risk factors for the disease and had no recent travel history or sick contacts. Acute diarrhea is not an uncommon manifestation of Legionnaires disease, although isolated diarrhea symptoms with the absence of concurrent respiratory symptoms and no risk factors for Legionella makes this case a diagnostic challenge, leading to possible delay in appropriate management. We are presenting this case to inform physicians of the possibility of Legionnaires disease presenting as an isolated gastrointestinal involvement with no clinical symptoms of pneumonia at presentation.