The purpose of this article is to describe the legal framework for controlling mosquito vectors of diseases transmissible to human beings in certain locations such as Reunion Island. A distinction is made between general legal measures for insect vector control and specific measures for mosquito control. Regionalization is a major factor in the legal framework for insect vector control, thus limiting the scope of action by the prefecture. Another factor involves the increasing role of an important new player, i.e., the regional health agencies. Mosquito vector control raises the need to impose and enforce measures on the general public as well as private citizens. Failure to comply with these measures is punishable by sanctions and fines with no diminishing effect on de jure implementation of control measures by public agencies.