In Septernber 2002, a 78-year-old woman who had received surgical operation of dissecting aneurysm was admitted to a general hospitaL She was of comatose status and was admitted to an intensive care unit (ICU) of the hospital, An attending nurse of the patient found numerous wiggling maggots with body length of 5 mm from her nasal and oral cavitjes in early October, Maggots were identified as the second-instar larvae of Sarcophaga Peregrina from the morphological characteristics of the larva and emerged male adult. The admission date to the ICU was rnore than 10 days prior to the discovery of 5 mm long S, Peregrina larvae. Therefore, this myiasis happened definitively inside the ICU,