This study investigates the working principle of compact spinning technology and the structural differences between Com4® yams spun by a Rieter ComforSpin® K40 compact spinning machine and conventional ring spun yarns. Differences in yam quality are observed. The higher tensile strengths and lower hairiness of the Com4 yarns are the key achievements of the compact spinning technology. However, limitations of the new technology are also revealed by investigating the quality of yams with different counts.