Human ehrlichiosis is not a common cause of acute respiratory distress syndrome (ARDS). Physicians should be aware of this life-threatening but treatable entity. Progression to ARDS may be related to delay in diagnosis and treatment. Fever, leukopenia, thrombocytopenia, and a history of tick exposure in an endemic area during the spring and summer months should alert the physician to the possibility of human ehrlichiosis, since a definitive diagnosis requires serologic testing that may take weeks to confirm. We describe a case of ARDS resulting from human ehrlichiosis. A unique feature in our case was that despite the early use of doxycycline, the patient had near fatal ARDS that responded dramatically to high doses of steroids.