Pumpkin (Tetsukabuto) peel extract was utilized to synthesize nanoparticles of magnesium. The nanoparticles were characterized using scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDS), X-ray diffraction (XRD), selected area electron diffraction (SAED), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), raman spectroscopy (RS) as well as Brunauer-Emmett-Teller (BET) analysis. The results showed that the synthesis of magnesium nanoparticles is possible by use of pumpkin peel extract. The characterization analyses indicated the presence of functional groups on the surface of the nanoparticles, which aided in the bioreduction of the metals to oxides. The nanoparticles can be applied in studies involving microbial agents due to their spherical shape, which allows for easy penetration into the cell wall of microorganisms. This work provides relevant information for the field of nanoparticles and the area of green synthesis.