Experimental solubilities are reported for N-hydroxyphthalimide (NHPI) dissolved in binary acetic acid + water solvent mixtures in the temperature range of (293.2 to 363.2) K. The mole fraction of water in the solvent mixtures x(water) ranges from 0 to 0.5882. The experimental results show that the solubility of NHPI in the range of 10(-2) to 10(-3) mole fraction increases significantly with an increase in temperature and x(water). The solubility data were correlated by a modified Buchowski equation, and the parameters h and lambda were regressed, which gave good agreement with all experimental data.