Aeromonas hydrophila is a gram-negative bacillus which has been rarely identified as a human pathogen except in immunologically compromised hosts. We have recently treated three patients for severe A hydrophila pneumonia and sepsis. Two of these patients were healthy young men who aspirated the organism from contaminated water associated with near drowning. One patient survived severe ARDS and gram-negative sepsis. A third patient with chronic renal failure acquired A hydrophila pneumonia at home and quickly died from the infection. A hydrophila is becoming more commonly recognized as a lethal pathogen and should be sought when gram negative infection is suspected.