Due to the lack of an approved vaccine against diarrhea, requirement of an efficient vaccine is urgently needed to fight against it. Enterotoxigenic E.coli is one of the major cause of bacterial diarrhea worldwide targeting children mainly under the age of 5 and despite of the severeness, till date there are no licensed vaccine and This book aims at developing a T cell epitope based vaccine that will be precise in triggering immune response efficiently. The most promiscuous T cell epitopes binding to the MHC(Major Histocompatibilty Complex) I and II will be identified through various immunoinformatics servers. Different computational vaccinology approaches were employed to assess several parameters including antigenicity, allergenicity, stability, localization, molecular weight and toxicity of the predicted epitopes required for good vaccine candidate to elicit immune response against diarrhea. There is no doubt that the outcome of this analysis performed in this book will led tothe potential vaccine that will fight against a global killer diarrhea and will save the society.