Using a laser monitoring observation technique, the solubilities of sodium cefotaxime ( A) in binary water ( B) + 2- propanol ( C) solvent mixtures were determined by the synthetic method from 278.15 K to 308.15 K and in the solvent composition ( x(C)(0)) range from 0.025 to 1.000. The results of these measurements were correlated by the combined nearly ideal binary solvent ( CNIBS)/ Redlich- Kister equation. For the seven mixtures studied, the CNIBS/ Redlich- Kister equation was found to provide a good correlation of the experimental data.