Agricultural plants and crops are being cultivated in higher amounts to compensate the food necessities of the growing world population. Pesticides are used extensively in order to protect them from harmful agents like insects, fungi, bacteria and herbs. Even though pesticides reduce the growth of pests, their presence in the environment poses adverse issues to the ecosystem. Owing to the extensive use of pesticides, some traces of pesticide residues eventually end up in the influent samples of Sewage Treatment Plants (STPs) through storm water runoff. Also, pesticides are being detected in STPs in relatively higher amounts in recent years. The conventional STPs not efficient to remove pesticides and the pesticides are let out along with the effluent of the treated wastewater. Hence there arises an inevitable need to characterize pesticides and study their behaviour and removal in STP. To do such characterization for screening purposes, United States Environmental Protection Agency (USEPA) approved Estimation Program Interface (EPI) Suite. In this paper, one module called STPWIN of EPI suite is employed to estimate the removal percent of 54 pesticides. It is found among the 54 approved pesticides that 40 pesticides have their removal efficiency less than 20% which elucidates that these pesticides must be prioritised. The results obtained in STPWIN and the chemical functional groups responsible for recalcitrance are discussed in detail in this paper. This study emphasizes that there exists a need to upgrade the existing STPs with due consideration to emerging contaminants like pesticides.