The Asian "tiger mosquito" Aedes albopictus has become established in the southern United States. The Centers for Disease Control has taken a number of steps to respond to the problem. Appropriate state and international agencies have been informed, and data on biology, public health importance and identification have been prepared and distributed to state and local agencies. Studies on insecticide susceptibility and vector competence are in progress, as is surveillance throughout the southeast, in cooperation with state and local agencies. The introduction of Ae. albopictus presents a major challenge to the mosquito control community.