The administration of exogenous somatotropin (ST) has been shown to increase lactation performance in mammals ranging from laboratory animals to humans. Therefore, keeping in view the importance of this hormone in milk and meat production, somatotropin cDNA has been cloned from a Pakistani buffalo, sequenced and expressed. The sequence obtained has been used for comparative modeling. The amino acid sequence of the buST cDNA was deduced using online available softwares. Secondary structure was predicted using NNpred and Psipred servers. ClustalW was used to produce sequence alignments. The 3D structure of the protein was obtained using Deep View (Swiss PDB viewer) and Modeler software. The predicted structure was evaluated with Procheck_NT. This book would interest you if you are a biotechnologist, pharmacist, biochemist or interested in bioinformatics. It can help you in over-production and purification of any ST using the methodology described in detail.