The present paper deals with modeling of the acute toxicity of 56 phenylsulfonyl carboxylates to Vibrio fischeri. Principal component factor analysis has been used as the data-preprocessing step for the selection of independent variables for the subsequent multiple regression analysis. The statistical quality of the best model using ETA descriptors is as follows: n 56, Q 2 0.726, R a 2 0.837, R 0.923, F 57.4 (df 5, 50), s 0.186, AVRES 0.136. Attempt has also been made to model the data set with different non-ETA parameters (topological indices including Wiener, Hosoya Z, molecular connectivity, kappa shape, Balaban J and E-State parameters apart from physicochemical parameters like AlogP98, MolRef and H-bond-acceptor) and the best model shows the following quality: n 56, Q 2 0.763, R a 2 0.798, R 0.903,