A new flow method and a traditional static method have been employed to obtain the critical temperatures and pressures for 11 compounds : 1,1-dimethylpropyl methyl ether, 1,1-dimethylethyl ethyl ether, toluene, ethylbenzene, (1-methylethyl)benzene, 1-methylethyl ethanoate, 2-pentanone, 2-hexanone, 2-heptanone, hexafluoroethane, and propene. Accurate critical densities were also obtained using a static method. The critical properties of stable compounds appear to be accurately determined by both methods. The flow method allows the determination of accurate critical properties for more reactive or thermally unstable compounds.