Background and objective: Atorvastatin calcium is an antihyperlipidemic agent that is characterized by low aqueous solubility and high membrane permeability. This study was designed to enhance the solubility and the dissolution rate of atorvastatin calcium in the water and physiological pH (pH 6.8) by using L-Leucine as solubilizing agent utilizing different solid dispersion methods. Methods: Solid dispersion masses were prepared by kneading method and solvent evaporation methods at different weight ratios (1:1, 1:2: and 1:4) of the drug to the carrier. Saturated solubility studies were carried out in aqueous media, and the in-vitro studies were performed in physiological pH Fourier transform infrared spectroscopy were used to detect any interaction between the drug and the carrier. Results: The kneading method increase the solubility of atorvastatin calcium by 1.27, 1.43, and 1.81 folds from kneading method 1, kneading method 2, and kneading method 3, respectively. The solubility of atorvastatin calcium in solvent evaporation 1, solvent evaporation 2, and solvent evaporation 4 was increased by 2.53, 2.66, and 3.1 folds (P = 0.002). Solvent evaporation 2 (1:2 ratio) was selected as the best formula in terms of dissolution profile because it has faster and complete drug release after 5 minutes when compared with solvent evaporation 1, kneading method 1, kneading method 2, and kneading method 3 and contain less amount of L-Leucine when compared with solvent evaporation 3. Fourier transform infrared studies indicated no chemical reaction between the drug and carrier. Conclusion: L-leucine significantly improved the solubility and dissolution profile of poorly water-soluble atorvastatin calcium.