Homogeneous nucleation rates of dioctylphthalate (DOP) [1,2-benzenedicarboxylic acid (bis-2-ethyl hexyl ester)] ranging from 0.032 to 16.3 drops cm−3 s−1 were measured as a function of supersaturation and temperature by using an upward thermal diffusion cloud chamber. The influence of thermodiffusiophoresis was included in raw data analysis. An empirical formula was used to fit measured nucleation rates over a supersaturation range from 33 to 68 and temperatures ranging from 364 to 396 K. A comparison with earlier published data on critical supersaturations of DOP showed consistency of both measurements.