The invention discloses a light emitting device and an organic light emitting display device including the same that are characterized in that some layers are formed to reduce the number of heterogeneous chronosphere faces through utilization of the same materials, and therefore driving voltage can be lowered. A light emitting device includes first and second electrodes facing each other on a substrate, a plurality of stacks stacked between the first and second electrodes and each including an EML so as to emit particular light, and a charge generation layer formed between the stacks so as to adjust charge balance therebetween and including an N-type charge generation layer and a P-type charge generation layer, wherein at least any one of the N-type charge generation layer and the P-type charge generation layer includes the same electron transporting material as that of an electron transport layer of one of the stacks that is adjacent to the N-type charge generation layer.