A method of preparing a positive active material for a rechargeable lithium battery including a) mixing a composite metal precursor and a lithium compound; b) firing the mixture to prepare a positive active material; c) mixing the resulting positive active material, a carbon coating material, and a solvent; and d) heat-treating the resulting mixture to provide a positive active material coated with the carbon coating material, wherein the carbon coating material is used in an amount of 1 wt % to 30 wt % based on 100 wt % of the composite metal precursor, lithium compound, and carbon coating material, the firing is performed at 400 to 900° C., and the positive active material provided in d) is represented by the following Chemical Formula 1, is provided. LiaNixCoyMnzM′kO2   [Chemical Formula 1] In Chemical Formula 1, each definition is the same as in the detailed description.