A method of fabricating a nitride semiconductor light emitting device is provided. The method includes growing a first group-III-nitride semiconductor layer on a substrate, the first group-III-nitride semiconductor layer having a top surface formed as a group-III-rich surface exhibiting a group-III-polarity and a bottom surface formed as a N-rich surface exhibiting a N-polarity. The method further includes selectively etching a N-polarity region in the top surface of the first group III nitride semiconductor layer, forming a second group III nitride semiconductor layer on the first group III nitride semiconductor layer to fill the etched N-polarity region and forming a light emitting structure including first and second conductivity type nitride semiconductor layers and an active layer on the second group III nitride semiconductor layer.