Pesticides are substances used to manage weeds, insects, rodents, fungi, and other undesirable species. Increased crop and livestock yields is one of the benefits of using pesticides, which has been essential in supplying the world’s growing population with food. However, their use presents serious risks to the environment and human health. Judicious and careful use of pesticides in agriculture and public health can result into maximizing the benefits of pesticides while reducing on the associated hazards. Prior knowledge of pesticide application technology and safety is vital in ensuring the careful and judicious use of pesticides. In this chapter, we discuss the need and benefits of pesticides, their categories and formulations, the adverse effects on human and environmental health, application equipment, safety considerations during application, calibration of the equipment, and the laws governing the manufacture, distribution and use of pesticides in selected countries.