The solubilities of carbon monoxide in benzene, naphthalene, phenanthrene, and pyrene were measured using a static equilibrium cell over the temperature range from 323.2 to 433.2 K and pressures to 23.3 MPa. The uncertainty in these solubility measurements is estimated to be less than 0.001 in mole fraction. The data were analyzed using the Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR) equations of state (EOS). In general, the two equations represent the experimental data well over the complete temperature range when one interaction parameter is used for each binary system. Marginal improvements in equation of state predictions are realized when an additional interaction parameter is used.