Pesticides are an essential part of modern life because of their utilization to check the development of undesirable living organisms. Over the past few decades, the application of pesticides has increased tremendously, not only confined to the agricultural sector but also widely utilized in homes and public places for the prevention of various pests. A major development in pesticide industries has been observed after the discovery of DDT (dichloro diphenyl trichloroethane) in 1939, and later BHC (β‐Benzene Hexachloride) and 2,4‐D (2,4‐Dichlorophenoxyacetic acid). In India, pesticides production started in 1952 after the establishment of the BHC plant in Kolkata. India is the second largest manufacturer of pesticides after China in Asia and holds the twelfth position at World level. Appropriate pesticides usage can protect our plants, animals, or house from destruction. However, improper pesticides usage might lead to damaging effects on plants, human health can be impaired, and expected pest control may not be achieved. Besides this, pesticides also contaminate soil, air, and water. Before using any pesticides, everyone should be aware of its user manual and proper management. Therefore, integrated pest management techniques should be promoted for pest control to minimize the dependency on these chemicals. Furthermore, the development of biopesticides should be encouraged that do not have harmful effects on non‐targeted organisms, which will be beneficial for the plants along with the human health and environment. The present chapter highlights the uses of pesticides, beneficial, and detrimental impacts of pesticides along with their mode of action in plants with special reference to photosynthesis.