Hibernating females of the Anopheles hyrcanus complex were collected at 4 different latitudes at the end of the hibernation period in March of 2005 and 2006, and species were confirmed by polymerase chain reaction (PCR) identification. At Paju (37.8°N; average temperature in December–February  =  −3.5°C) 74.6% of the females collected were An. pullus and 22.4% were An. sinensis. At Seosan (36.8°N; December–February average temperature  =  −1.0°C) and Buan (35.7°N; December–February average temperature  =  0.4°C) 14.7% and 14.8% were An. pullus, and 85.3% and 85.2% were An. sinensis, respectively. At Haenam (34.6°N; December–February average temperature  =  3.1°C) only An. sinensis was found. Our preliminary results indicate that An. sinensis, unlike An. pullus, is not adapted to survive in cold weather.