The solubilities of trimethoprim (TMP) in methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, acetone, and tetrahydrofuran were measured using a laser technique in the temperature range from (278 to 333) K. The results were correlated with a modified Apelblat equation, which can be used as a useful model in the refining process of TMP.