The immune system is an integrated organization, comprising of specific organs, cells and molecules playing a crucial role in the maintenance of health. The purpose of this paper is to give a mechanistic overview of toxic effects of various chemicals and pharmacological agents, and their interaction with the various components of the immune system that leads to modulation of the immune responses. Studies suggest that many chemical agents present in the environment like; heavy metals, agrochemicals, and various types of hydrocarbons possess immune toxicity and cause either structural, functional or compositional changes in various components of the immune system that alters immune response. There is present a complex bidirectional relationship between central nervous system (CNS) and the immune system. And receptors for neuropeptides, neurotransmitters, and hormones are located on lymphoid organs. Therefore, we are of the opinion that Endocrine Disrupting Chemicals (EDCs) present in our environment may be indirectly involved in causing immune toxicity via neuroendocrine channels, and vice versa many neurological disorders may be associated with environmental pollutants utilizing immuno-neuroendocrine pathways.