A traumatic hand laceration in a previously health 17-year-old boy resulted in a rapidly progressive palmar space infection, with gas formation, in the soft tissues caused by Aeromonas hydrophila. Typically associated with aquatic injuries, A. hydrophila was not initially suspected since the injury did not occur near water. Physicians treated trauma-related soft tissue infections, particularly when the initial Gram stain shows many polymorphonuclear leukocytes and gram-negative bacilli, must consider the possibility of an Aeromonas infection even if the injury occurred in a nonaquatic environment. Appropriate therapy, including vigorous wound debridement and an aminoglycoside antibiotic, will be curative in an immunologically normal host.