Bacillus thuringiensis cry proteins are effective in controlling harmful insects. However, the mechanism of Bt protein pesticidal action is not well understood. It is assumed that the pesticidal protein has affinity for specific receptors in the midgut of the susceptible larvae and binds irreversibly to create holes in the gut leading to eventual death of the target larvae. Main aim of the research is to identify, purify and characterize Bt delta endotoxin receptor in important pest American bollworm (Helicoverpa armigera). The study presented in this thesis is endeavored to; (1) discovery of a receptor protein, (2) purification of the receptor,(3)cloning of the newly discovered protein gene in E.coli, (4) expression studies on recombinant protein, (5) Complete sequencing of the cloned gene. The structural gene was cloned in expression vector. The cloned gene was sequenced and studied expression. The cloned, expressed,purified receptor protein was found to have characteristics of native protein of H.armigera. A new method for quick detection of Bt-receptor in crude BBMVs extract, was established.The sequence has novelty and Accession # A59445)or Q7M4K6.