The article is devoted to the NakhchivanYallis, which have a special place and role in the musical culture of Azerbaijan. Based on the notes of NakhchivanYallis and the researches carried out, classification of yalli dances has been conducted, and the area of spread has been determined. The writing of the Yalli names has been revealed in connection with the terrain, man, tribal names, mythological outlook,and actions. The musical instruments used in accompaniment of yalli dances have been characterized. Comparative analysis of yallis in the areas of Azerbaijan and Turkey has been put forward as an important issue. The Azerbaijani folk yallis, one of the oldest collective plays in the world, are a rare example of creativity that combines choreography, instrumental and vocal music. Yalli dances are one of the oldest folk dances in terms of genre, performance, and expression. For centuries, Nakhchivan has been known as the "homeland of yallis", "the land of yallis" among Caucasians, both Near and Middle East and Europe. Yalli is an ancient cultural monument of Nakhchivan's traditional musical heritage.