A new frictional constant is suggested to characterize the surface mechanical properties of 1×1 rib-knitted cotton fabrics. This study examines the influence of structural variables on the frictional properties of knitted cotton fabrics. The results indicate that both the loop length and the yarn linear density influence the fabric-on-fabric frictional properties. The variation in the structure of knitted fabrics is reflected in the frictional properties as defined by the new frictional constant. A statistical relationship is established between the frictional constant and the variables that exert some influence such as the loop length and the yarn linear density.