The solubility of sirolimus drug in different organic solvents, viz., acetone, chloroform, methanol, ethanol, and dichloromethane, has been measured for the temperature range of (295 to 345) K by a gravimetric method. The relation between solubility and crystal size formation has also been studied. It was found that the higher the solubility of material, the larger the crystal size and vice versa. The stability of crystals has been measured, and it was found that smaller crystals have a moderate level of stability when compared with that of larger crystals. From the observations of the present study, it may be suggested that for cardiovascular applications of sirolimus drug one can use ethanol and methanol as a solvent for deriving crystals of less than 400 nm size.