The impurities in pharmaceuticals are superfluous chemicals that remain with the active pharmaceutical ingredients (APIs) or develop during formulation or upon aging of both pharmaceutical ingredients and formulation. The presence of these superfluous chemicals even in small amount may manipulate the safety and efficacy of pharmaceutical product. Some of these impurities also known as genotoxic impurities (GIs) could be mutagens or carcinogens and cause adverse effects on the human body even in trace amount. Starting materials, reagents, intermediates, by products, and degradation products are often found as impurities in active pharmaceutical ingredients. There are several regulatory guidelines and position papers focused on controlling the amount of impurities within specified limits. The present compilation gives an account of updated information about GIs and reviews the regulatory aspects for GIs in active pharmaceutical ingredients/drug formulations. A detailed discussion about control strategies in the context of GIs is also described precisely.