There is a need to develop environmentally friendly materials, especially plastics, that minimize environmental pollution. In this sense, polypropylene (PP) composites were produced with 20 wt% of Macaiba almond powder (MA*) and compatibilized with SEBS-MA and EPDM-MA to carry out a biodegradation investigation of these composites. Mechanical properties (impact, tensile), heat deflection temperature (HDT), scanning electron microscopy (SEM), and Fourier transform spectroscopy (FTIR) experiments were performed. These analyses verified that the best plasticization was reached in the composites with 15% of SEBS-MA and EPDM-MA, indicating an interaction between phases. The impact strength and elongation at break of the PP/MA*/EPDM-MA and PP/MA*/SEBS-MA composites increased significantly, suggesting tough behavior. Biodegradation occurred in the soil for 120 days, and both PP/MA*/10EPDM-MA and PP/MA*/15EPDM-MA demonstrated a mass loss of about 4.68% and 4.0%, respectively. Although PP is not biodegradable, the results show that macaíba almond powder can biodegrade in the PP matrix.