CCAST, World Lab, Beijing 100080, Peoples R China
; Acad Sinica, Inst High Energy Phys, Beijing 100039, Peoples R China
; Acad Sinica, Inst Theoret Phys, Beijing 100080, Peoples R China
Exclusive semileptonic B decays into excited charmed mesons are studied with QCD sum rules in the leading order of heavy quark effective theory. Two universal Isgur-Wise functions tau and zeta for semileptonic B decays into the four lowest lying excited D mesons (D-1, D-2*, D-0', and D-1') are determined. The decay rates and branching ratios for these processes are calculated. [S0556-2821(99)07301-4].