Polymeric materials are present in all spheres of human life. Their use generates large amounts of polymer waste, which must be properly managed to prevent it from posing a hazard to humans and the environment. Mechanical recycling has proven to be an effective way to process thermoplastic polymer materials, allowing their reuse for various purposes. Although thermoplastics theoretically have a virtually unlimited potential for multiple recycling cycles without loss of properties, impurities that may be present in the polymer material can potentially have a negative impact on properties. In this study, the effect of multiple cycles of mechanical recycling on the properties of polypropylene (PP) was investigated for this very reason. The samples whose properties were studied were prepared by mixing pure PP, industrially recycled PP, iron(III) oxide and metallized PP from packaging waste. After the mixtures were prepared, four cycles of mechanical recycling by extrusion were performed. In order to monitor the effects of multiple cycles of mechanical recycling on the properties, characterization was performed using different methods. Differential scanning calorimetry (DSC) was used to determine the melting temperature (Tm) and crystallization temperature (Tc), as well as the heat flows due to endothermic (ΔHm) and exothermic (ΔHc) changes. The degree of crystallinity (Xc) was also calculated based on the data. Changes in the morphology and composition of the tested samples were observed by scanning electron microscopy. In addition, the melt flow rate (MFR) was determined and finally the mechanical properties of the samples were tested using a universal testing machine. The properties were monitored after each recycling cycle. The research results showed that multiple mechanical recycling cycles did not have significant negative effects on the chemical structure and properties of PP that would hinder its application. Mechanical recycling has been shown to be an effective method for the recovery of PP.