Enantioseparation data of mitotane (o,p'-DDD) have been obtained and thermodynamically analyzed. A diallyl-L-tartardiamide-based stationary phase (Kromasil CHI-TBB column) was used for chiral separation and CO2 added to 14% of methanol at 160 bar was used as mobile phase in a temperature range of 303.15-313.15 K. The thermodynamic parameters accounting for the retention and the separation were determined by means of van't Hoff plots. The isoenantioselective temperature was calculated to be 331.55 K. The enantioseparation process was enthalpically driven under experimental conditions.