This paper describes the measurement of packing density and radial packing density of newly developed three-layered, wool structure yarn for pile carpets. Three different varieties of Indian wool, in terms of fibre diameter, medullation and bending rigidity, were strategically positioned in the (ring spun) yarn cross-section. The measurements of all the researched yarns have shown that radial packing density is neither uniform across the yarn cross-section nor maximum at yarn core. The maximum packing density of these yarns occurs at some different distances from the yarn axis and it sharply decreases from that point towards yarn surface. In general, all the yarns are seen to have slight hollowness near their axis. The possible mechanism of the fibre density distribution in the yarn cross-section is also discussed.