The pressure p-temperature T projections of solid-liquid-gas (S-L-G) three-phase coexistence lines for the carbon dioxide + S-(+)-ibuprofen system and the carbon dioxide + RS-(+/-)-ibuprofen system were measured by the first melting point method in which the initial appearance of the liquid phase was observed. The experimental p-T projections of the S-L-G lines for the two systems were quite different from each other. The experimental p-T projections of the S-L-G lines were also correlated by the Peng-Robinson equation of state with a binary interaction parameter introduced into an attraction term. The present model gave good correlation results for all of the experimental S-L-G lines with maximum average absolute relative deviations of 0.14% for the carbon dioxide + S-(+)-ibuprofen system and 0.90% for the carbon dioxide + RS-(1)-ibuprofen system.