The minimum energy conical intersection (MECI) geometries play an important role in photophysics and photochemistry. Although a number of MECI geometries can be identified using quantum chemical methods, their chemical interpretation remains unclear. In this study, a systematic analysis was performed on the MECIs between the singlet (S-0) and lowest singlet excited (S-1) states of organic molecules. The frozen orbital analysis (FZOA), which approximates the excited states with minimal main configurations, was adopted to analyze the excitation energy components at the S-0/S-1 MECI geometries as well as the S(0 )and S-1 equilibrium geometries. At the S-0/S-1 MECI geometries, the HOMO-LUMO gaps decreased as expected but did not disappear. The remaining gaps were balanced with the HOMO-LUMO Coulomb integrals. Furthermore, we discovered that the HOMO-LUMO exchange integrals became approximately zero. On the basis of this fact, a systematic interpretation of the S-0/S-1 MECI geometries has been described.