Fibre reinforced concretes are nowadays widely adopted in some constructions sectors. Their increasing adoption has been supported by many research studies that guided the definition standards and guidelines for testing and design. Nevertheless some aspects of their behaviour have not yet been deeply studied and understood; for instance the effect of temperature variations on concretes with polymeric fibres has received limited attention in the literature. In this framework, the present paper presents a study on the influence of temperature variation on macro-synthetic fibers for FRCs. In particular, single polypropylene fibers were tested at different temperatures, 20°C, 40°C, 60°C, 80°C, and different rates, under tensile load, analyzing how the increment of temperature affects their strength and elastic modulus.