One of the most prominent semiempirical molecular orbital theory methods has been applied to discuss the electronic and conformational aspects of coenzyme Q known also as ubiquinone. Calculations were made by means of the approximate SCF MO method, applying the MINDO/3-Forces program. The quilibrium molecular geometry of coenzyme Q1 has been calculated beginning with its building block, the pbenzoquinone molecule, passing through coenzyme On molecule, The reduced forms of coenzyme Q0 and coenzyme Q1 were also considered in this work, and their equilibrium molecular geometries were calculated. The obtained results helped to explain the biological behavior of this vital molecule involved in the oxidationreduction process carried out within the mitochondria of living cells. The results concerning the electronic aspects of the molecules studied showed that, in all the oxidized forms, the ELUMO had a negative value in which an easy reduction of the molecule is expected. While in the reduced forms the EHOMO had higher values than in the oxidized forms, a condition needed to make the loss of an electron from the molecule easier. This clearly explains the behavior of coenzyme Q as an electron carrier throughout the electron transport system in living organisms. Results concerning conformational aspects of the molecules studied showed that the methyl group in these molecules prefer a form in which one of its hydrogen atoms is perpendicular to the plane of the molecule. This preferable conformation is expected to be stabilized through hyperconjugation. In molecules that have two adjacent methoxy groups, the obtained results shows that the molecule is stabilized at a conformation in which both methoxy groups are out of plane in directions opposite to each other, such that the mutual steric hindrance of both methoxy groups is minimized. The conformation of coenzyme Q1 was stabilized in a form such as the isoprene unit was rotated out of plane toward the nearby oxygen atom.- As for the reduced forms of coenzyme Q0 and coenzyme Q1, their conformations were stabilized at a form in which one of the protons lye out of plane while the other stays within it. As well as broadening the application of quantum chemistry to biomolecules, it is hoped that this study would shed some light on the participitation and functioning of coenzyme Q. at least on the strength of a theoretical approach.