Cuprous oxide (Cu2O) nanoparticles (Nps) were synthesized using the vegetable waste viz. Daucus carota (Carrot) peel and agro wastes Cocos nucifera (Coconut) husk and Artocarpus heterophyllus (Jackfruit) seed. X-ray diffraction analysis confirmed the formation of cubic Cu2O nanoparticles having high crystallinity. Microscopy analysis of the synthesized Cu2O nanoparticles using D. carota and A. heterophyllus revealed spheroidal-like cluster formation, whereas rice spikelet nanostructures were observed in the case of C. nucifera synthesized Cu2O Nps. Energy-dispersive X-ray spectra of all the nanoparticles showed the presence of Cu and Oin the desired ratio, confirming the stoichiometry. Fourier transform infrared spectra revealed the presence of the functional groups responsible for the synthesis of the nanoparticles. The antimicrobial activity studies of the synthesized Cu2O nanostructures showed satisfactory results against the bacterial and fungal species. Hence the vegetable and agro-waste may be regarded as a biofactory for synthesizing the Cu2O nanoparticles. © 2021 Wiley-VCH GmbH