Spandex is an elastomeric manufactured fiber and amalgamation of it effects various properties of yarn and fabric. In the present study,single jersey knit fabrics were developed using cover spun yarns of lyocell and spandex. Cover spun yarns were developed using 20D and 40D spandex filament placed in the core of the yarn whereas lyocell yarn was used as the sheath. The aim of the study is to determine theeffect of spandex count on structural properties of single jersey knit fabric. The investigation showed that manifestation and change in denier of spandex effects the tested properties of the developed fabrics. Statistical analysis also showed that results were significant for fabric weight, fabric thickness, wales per inch, courses per inch and stitch density