This paper introduces a simple procedure for developing composite materials with antibacterial and biocompatible properties using polylactic acid (PLA) and polypropylene (PP). These composites incorporate three variants of zeolites in different percentages as filler agents: pure zeolite (PZ), copper ion-saturated zeolite (LZ), and copper-ion-saturated zeolite with copper oxide nanoparticles (LZ-nCu). The composites were prepared by the extrusion method and manufactured by injection molding. The impact of these zeolites on various material properties was evaluated, including morphology, thermal stability, mechanical properties, antibacterial capacity, biocompatibility, water absorption, and chemical resistance. The results demonstrated that (i) the incorporation of zeolite into the PP matrix improved thermal stability and increased the tensile modulus of the composites. For PLA-based composites, although there was a slight decrease in these values compared to pure PLA, they remained within acceptable ranges; (ii) zeolite LZ and LZnCu composites at 5 and 10 % by weight effectively inhibited the growth of Gram-positive and Gram-negative bacteria within a maximum of 2 h of contact; and (iii) composites containing 10 % by weight of PZ, LZ, or LZ-nCu showed reduced mechanical properties due to a tendency to form agglomerates. Additionally, LZ and LZ-nCu composites with the same percentage proved highly toxic to human gingival fibroblast cells (HGFs). PLA/LZ-nCu at 5 % and PP/LZ at 5 % composites exhibited antibacterial properties with bactericidal effects upon contact, high biocompatibility, and lower water absorption compared to the pure polymeric matrix. These results highlight the operational effectiveness of the procedure and suggest the potential of these composites in biomedical applications, such as in vitro dentistry, without contamination risks.