The excessive and ever-increasing use of synthetic pesticides as a consequence of the rush to enhance agricultural output has had enormous negative consequences. They have grown as a major contaminant of soil and water, are very hazardous to humans and animals. Past few years have seen a significant increase in the usage of essential oils (EOs) derived from aromatic plants and are generally considered as low risk pesticides, owing to their popularity among organic growers and ecologically concerned customers. EO-based pesticides benefit also from the ongoing decline in the use of conventional pesticides as a result of regulatory action and rising pest resistance . The purpose of this chapter is to summarize the primary applications of essential oils as pesticides and its biological activity with different class of organisms such as insects, bacteria, fungi, Acari etc., as documented in the scientific literature. The chapter concludes with a section summarizing the major findings of the literature and discussing potential directions for the use of Essential oils as pesticides of the future