Tryptophan methyl-ester (TrpME) is derived from a natural amino acid, which contains an indole heterocycle. This gives tryptophan its absorption and fluorescence spectroscopic properties. TrpME has become a commonly tool used in many fields namely medicine which is considered as the most important one. In front of his major importance, we found interesting to make a theoretical study on the conformational analysis by DFT/B3LYP method with 6-31G(d,p) basis set to find the most stable form of TrpME. Seven staggered stable conformers were observed on the torsional potential energy surfaces, it is shown that TrpME_1 conformer (D1= 178.62