Epidemiological evidence arising mainly from studies undertaken in sub-Saharan Africa suggests that sleeping under insecticide-treated mosquito nets is a cost-effective and efficacious method of controlling malaria. For this reason, promotion of use of insecticide-treated nets (ITNs) has become a key malaria control strategy. In 1999, the United Nations Children's Fund (UNICEF) and WHO set the goal of providing 32 million nets and 320 million net treatments a year for the next 10 years to protect 80% of African households against malaria. All pesticides are toxic by nature and are associated with adverse health risks that depend on the toxicity of each chemical, as well as the type and degree of exposure. Thus, massive scale-up of use of ITNs in malaria endemic poor countries can be expected to present tangible risks to health, especially where the insecticides for net treatment and re-treatment are handled mostly by untrained persons in uncontrolled settings. This paper examines potential health risks of mass use of ITNs in malaria endemic poor countries and calls for the implementation of strategies to minimize potential risks through careful selection of products, appropriate labeling (including labeling in the local languages of the user communities), pesticide safety education of the public and training of health personnel, and active monitoring of adverse health effects to document actual and potential hazards, and to facilitate planning of mitigation efforts.