Faba bean isamang the most strategic crops in Egypt and suffering from many destructive diseases especially chocolate spot caused by Botrytis fabaeSard.whichcan reduce yield production. Effect of chitosan nanoparticles (ChNPs) and silver nanoparticles (AgNPs) with average particle size of 7.54 and 8.043 nm, respectively at five concentrations (20, 40, 60, 80 and 100 ppm), as well asrecommended dose of carbendazim (CZ) 100 g/100L (field rate) were studiedin vitroagainst aggressive isolate of Botrytis fabae (B.f4). All concentrations significantly inhibited the radial growth of B.f4 compared with the control treatment. In vitroresults showed that ChNPs followed by AgNPs were effective over conventional chemical fungicide CZ. Where the radial growth of B.f4 decreased by increasing concentration of thedifferent materials especially ChNPsat 20-40 ppmrecording 73.33% and 100% growth inhibition, respectively. While 100 ppm of AgNPs and recommended dose of CZ rate of 75.33% and 46.11% growth inhibition, respectively.In addition, scan electron microscope (SEM) showed that, the mycelium ofB.f4treated by AgNPsdid not have detruation changes at 20 ppm. Contrary to B.f 4 mycelia treated with ChNPs 20 ppm exhibited seriously shrunk after 72 h posttreatment in relative to the control. The antifungal effect of ChNPs, showed markedcovered distorted mycelia. Most B.f4 spore morphology treated withAgNPs20 ppm appeared to be shrunk and abnormal shape 72 h post treatment compared with the control. In addition, AgNPs lead to deforming B. fabae spores and explosion of others.On the other hand, spore production of B. fabae treated with ChNPs20 ppm was completely inhibited 72 h post treatment.The obtained results offers a possibility of developing new manufacturing fungicides using chitosan and silver nanoparticles as substances for save control offaba bean chocolate spot disease and minimize the impact of conventional fungicides in the agri-ecosystem