Colletotrichum gloeosporioides and Lasiodiplodia theobromae, causing anthracnose and stem-end rot are the major post-harvest pathogens of mango worldwide, causing 25-40% post harvest loss globally. The present study was conducted to evaluate the effect of a natural volatile, hexanal, on the mycelial growth and spore germination of C. gloeosporioides and L. theobromae. Preliminary screening was carried out with sixteen different concentrations of hexanal on the mycelial growth of the pathogens. Further, the minimum inhibitory concentration of hexanal was determined. The effect of hexanal on the germination of spores of both the pathogens was determined by incubating the spores of the respective pathogens in hexanal up to 24 h. Observation under scanning electron microscope revealed that hexanal caused distortion in the mycelial strands and malformation of spores of C. gloeosporioides and L. theobromae. Unripe mango fruits were subjected to hexanal dip and inoculated separately with the pathogens.