An organic light emitting display device comprising: a first semi-transmissive electrode on a substrate; a first emission part on the first electrode, the first emission part including a first hole transport layer, a first emission layer, and a first electron transport layer; a second emission part on the first emission part, the second emission part including a second hole transport layer, a second emission layer, and a second electron transport layer; a third emission part on the second emission part, the third emission part including a third hole transport layer, a third emission layer, and a third electron transport layer; and a second reflective electrode on the third emission part, wherein a first distance between the substrate and the first emission layer, a second distance between the first emission layer and the second emission layer, a third distance between the second emission layer and the third emission layer, and a fourth distance between the third emission layer and the second electrode are different from each other, wherein a first charge generation layer is formed between the first emission part and the second emission part and a second charge generation layer is formed between the second emission part and the third emission part, wherein the second distance comprises thicknesses of at least the first electron transport layer, the first charge generation layer and the second hole transport layer between the first emission layer and the second emission layer, and the second distance is within a range from 25 nm to 50 nm, and wherein the first emission layer and the third emission layer each comprise one of a blue emission layer, a sky blue emission layer, and a deep blue emission layer, and the second emission layer comprises one of a yellow-green emission layer and a green emission layer. a first semi-transmissive electrode on a substrate; a first emission part on the first electrode, the first emission part including a first hole transport layer, a first emission layer, and a first electron transport layer; a second emission part on the first emission part, the second emission part including a second hole transport layer, a second emission layer, and a second electron transport layer; a third emission part on the second emission part, the third emission part including a third hole transport layer, a third emission layer, and a third electron transport layer; and a second reflective electrode on the third emission part, wherein a first distance between the substrate and the first emission layer, a second distance between the first emission layer and the second emission layer, a third distance between the second emission layer and the third emission layer, and a fourth distance between the third emission layer and the second electrode are different from each other, wherein a first charge generation layer is formed between the first emission part and the second emission part and a second charge generation layer is formed between the second emission part and the third emission part, wherein the second distance comprises thicknesses of at least the first electron transport layer, the first charge generation layer and the second hole transport layer between the first emission layer and the second emission layer, and the second distance is within a range from 25 nm to 50 nm, and wherein the first emission layer and the third emission layer each comprise one of a blue emission layer, a sky blue emission layer, and a deep blue emission layer, and the second emission layer comprises one of a yellow-green emission layer and a green emission layer.