The occurrence of Culex (Barraudius) inatomii Kamimura and Wada was observed from a large reedy marsh with fairly polluted brackish water near the coast of Ulsan, Korea, at an industrial complex. On average, 263.6 larvae per dip (450-cc dipper) were collected, and 408 females were caught by human biting collection in an hour. A CDC light trap set up outdoors collected 511 Cx. inatomii (96.8% of the total mosquitoes). The occurrence of this rarely reported mosquito raises questions about the effects of habitat modification and the need for further study.