A positive active material for a rechargeable lithium battery includes a first compound represented by Chemical Formula 1, and a second compound having a smaller particle diameter than the first compound and represented by Chemical Formula 2, wherein the first compound and the second compound have a Ni content of about 50 at % to about 60 at % based on a total amount of metal elements excluding Li. A rechargeable lithium battery including the first compound and the second compound satisfies Relation 1: Vs