In this study, the structural and conformational analysis of the O-substitute derivatives of isoflavanes were investigated and explained according to theoretical results. Isoflavanes attracted much attention due to their many health benefits. They have protection properties against breast cancer, heart disease and prostate cancer. Isoflavanes are secondary metabolites of plants and vegetables and they are present in foods as the form of glucosides. The structural and electronic properties of arvensan and isosativan were investigated computationally by performing the molecular mechanics (MM+ force field), the semi-empirical self-consistent-field molecular- orbital (AM1) calculations. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were calculated by means of density functional theory (B3LYP) and ab initio (HF) methods with the 6-31G basis set. They were carried out using HyperChem 7.5 and Gaussian 03 program package.