This study presents the mechanical properties of weft knitted sandwich fabrics (bursting strength) and the effect of the raw materials used. Two types of fabrics, with and without reinforcing yarns, were analysed. To determine the influence of the raw material type, a combination of three structure variants were obtained by changing the position in the structure architecture of two types of raw material: Kevlar® and linen yarns. Each of these variants was studied at three levels of density, given by the position of the quality cam, in order to determine the influence of this parameter. Tests were organised in two stages: the first concerned the bursting behaviour of single layer fabrics, and the second considered the study of more layers of sandwich fabrics with different orientation. Satisfactory results were obtained after this study regarding the possibility of replacing the high-performance yarns with natural ones.