Despite its biological importance, little is known about the solubility properties of tiamulin hydrogen fumarate in different solvents. This work presents solubility of tiamulin hydrogen fumarate in acetone, acetonitrile, ethyl acetate, ethyl formate, and butyl acetate from (288.2 to 318.2) K at atmospheric pressure. The solubility data have been correlated by the Apelblat equation.