Adult respiratory distress syndrome (ARDS) is frequently associated with septicemia. However, the incidence, risk factors, and prognosis are poorly defined. Therefore, during a nine-month period, 116 consecutive patients with septicemia were analyzed. ARDS occurred in 21 of 116 (18 percent) of septicemic patients. Shock preceded all cases of ARDS but occurred in only 15 percent of patients without ARDS (p less than 0.001). Thrombocytopenia was more frequent (62 percent vs 16 percent, p less than 0.001). Age, sex, compromised host status, type of septicemia, temperature, and white blood cell count were not significantly different between the two groups. It is concluded that ARDS frequently complicates all forms of septicemia. It is usually preceded by shock and thrombocytopenia and significantly worsens the prognosis.