Today high performance fibres with uniquely inherent properties are used for many technical areas such as resistance to heat and flame, chemicals, stabs and cuts; protective clothing and gloves for firefighters, military and industry. In this study, some technical core-spun yams, which can be used in the development of protective textiles were produced with various high performance fibres in three core-sheath ratios (19/81%, 37/63%, 56/44%) by using a modified ring spinning frame. Short staple para-aramid, meta-aramid and PES Trevira(R) (flame retardant) fibres were used as sheath and multi filament yarns of 110 dtex linear density (E-glass, PES Trevira(R), PA HT, PP, PES HT, Technora(R) T240 and Dyneema(R) SK75) as the core. The data obtained from tensile testing and the effects of sheath, core and core-sheath ratio on tensile properties were analysed statistically. The results revealed that the tensile properties of core-spun yarns show different tendencies with respect to the type of fibres in core, sheath and different core/sheath ratios. Higher tensile strength is noticed in core-spun yarns with para-aramid sheath fibres followed by PES Trevira(R) and meta-aramid, and vice-versa in case of elongation. Dyneema(R) and Technora(R) core-spun yams exhibit the highest and PES-Trevira(R) the lowest tensile strength values. Highest elongation values were observed for core-spun yams with PP filaments.