The authors describe a case of nosocomial myiasis of cavities caused by larvae of the fly Lucilia sericata (Meigen 1926), in a patient hospitalized at the resuscitation unit after a motor car accident where he suffered fractures of the skull and other injuries. On the fourth day in hospital in the nasal and oral cavity of the patient larvae of the 1st and 2nd instar of the mentioned species were detected. The ova were laid in hospital. L. sericata is the most frequent causal agent of tissue, cavity, ocular and urogenital human myiasis in Central Europe. In Czechoslovakia so far seven cases were recorded, incl. three nosocomial ones. Myiases usually attack immobile, injured or severely ill people in summer. It is important to draw attention to the hazard of myiases under exceptional conditions.