The solubilities of 4-amino-3,6-dichloropyridazine (ADCP) in an ethanol + water mixture were determined from (303.15 to 323.15) K with an interval of 2.5 K at atmospheric pressure using the synthetic method with a laser monitoring observation technique. The solubility of ADCP was found to increase with the rise of temperature and the mole fraction of ethanol. The experimental solubilities were regressed with different models including the modified Apelblat equation, combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) model, and the hybrid model. For the six mixture solvents studied, all of the mean percentage deviations with Apelblat equation are less than 1.7 %.