An electrolyte for a lithium secondary battery, and a lithium secondary battery including the same are provided. The electrolyte includes: a cyclic ester; an organic solvent including a nitrile-containing solvent represented by Formula 1 at a content ranging from 1 to 5% by volume; and a lithium salt, R—C≡N  (1) wherein R is selected from the group consisting of a C1 to C10 aliphatic hydrocarbon, a C1 to C10 halogenated aliphatic hydrocarbon, a C6 to C10 aromatic hydrocarbon, and a C6 to C10 halogenated aromatic hydrocarbon. The electrolyte can improve swelling characteristics and discharge capacity characteristics at a low temperature, and realize equal or better performance in characteristics such as capacity, life span and the like, as compared to a conventional carbonate-containing electrolyte.