In the present study, the effects of administering ethanol to adult male rats on the distribution of the low fluorescence population (LFP) and high fluorescence population (HFP), and the rhodamine-123 fluorescence intensity of these groups of mitochondria are analyzed by flow cytometry. Our results show that ethanol administration to adult male rats induces a redistribution of the HFP and LFP mitochondrial populations leading to an increase of the less functional HFP mitochondria. In addition, ethanol induced an increase in the mean intensity of green fluorescence of the HFP that is probably related to an increased number of rhodamine-123 binding sites per mitochondria resulting from mitochondria enlargement.