The present invention provides novel peptides, having the structural formula (I) showed GIP, GLP-1 & Glucagon-receptors triple-agonistic activity. These peptides exhibit increased stability to proteolytic cleavage, especially against DPP-IV (Dipeptidyl peptidase-IV) enzyme. These peptides can be delivered by parenteral routes of administration, for the treatment or prevention of diabetes, obesity and related metabolic disorders. The present invention thus discloses novel peptides as GIP, GLP-1 & Glucagon-receptors triple-agonist having the following structure (I) A-Z1-Z2-Z3-Z4-Z5-Z6-Z7-Z8-Z9-Z10-Z11-Z12-Z13-Z14-Z15-Z16-Z17-Z18-Z19-Z20-Z21-Z22-Z23-Z24-Z25-Z26-Z27-Z28-Z29-B (I)
