Disclosed are a non-aqueous electrolyte for a rechargeable lithium battery and a rechargeable lithium battery including the non-aqueous electrolyte, and the non-aqueous electrolyte for a rechargeable lithium battery includes a lithium salt; a non-aqueous organic solvent; and trialkylsilyl borate as an additive, wherein the non-aqueous organic solvent may include a solvent having a low melting point of less than or equal to about −50° C. and ionic conductivity of greater than or equal to about 6 mS/cm at 25° C.