Quality control as an important element of production management includes testing of raw materials and products at every stage of the production process. Among the raw materials used in many industries, polymer materials are playing an increasingly important role, e.g. elastomers with good elastic properties, such as EPDM (ethylene-propylene-diene rubber) and CR (chloroprene rubber). For this reason, they can be used in various industries (e.g. automotive, aviation, construction). During production, these raw materials are subjected to various types of reinforcing modifications (cross-linking, fibers reinforcement) and control tests, such as assessment of mechanical properties. The aim of the work was therefore to demonstrate, which cross-linking method is more advantageous in terms of these properties, and also whether and to what extent replacing fibres from typical chemical synthesis with recycled fibres will affect the mechanical properties of the product. Therefore, the mechanical properties were assessed for rubber mixtures obtained from synthetic rubbers: CR and EPDM (cross-linked with sulfur and peroxide), in unreinforced form and reinforced with polyamide fibers of two types: I – from primary synthesis, II – from recycling. The studies showed that among the unreinforced mixtures, the best mechanical properties were characteristic of the EPDM mixture cross-linked with sulphur. Reinforcement of this mixture with type I fibres resulted in the greatest increase in strength Rm, and with type II fibres a slightly smaller one. At the same time, it was found that the type of fibers did not cause significant differences between the elongation Eb of the reinforced mixtures. The research results therefore indicate the possibility of using recycled fibers in the process of reinforcing rubber compounds, while maintaining relatively good product quality. This is all the more justified because this action fits into the concept of sustainable development.