Number of filaments, which constitute filament yams, is a parameter significantly affecting the structure and properties of both the manufactured yarn and the fabric derived from such yarn. This parameter varies according to the number of spinneret holes on the spinneret element used in production. Today, the number of filaments that should exist in the yarn's cross section in filament yarn production may vary according to the customer choices and the usage areas, and they are also preferred for product development studies, as production data in different values. Since the change in the number of filaments affects a single filament, which is the production raw material, and therefore the structure of the final yarn, it is expected that the properties of both the manufactured yarn and the fabric is affected from this situation. This study analyses the effects of filament number on the properties of partially oriented yarn (POY) and textured yam derived from such yarn, and tries to understand the effects of this factor on properties of POY and textured yarn, with the help of statistical analysis.