Here, the authors describe a simple method to formulate the nanodispersion of hexaconazole (hexa); henceforth, referred to as nanohexaconazole (N-hexa) that is water soluble and effective against several species of Aspergillus. Size and shape of the prepared nanocomposite was determined with high-resolution transmission electron microscopy and field-emission scanning electron microscopy. Nanohexaconazole structure was further confirmed by Fourier-transform infrared spectroscopy and gas chromatography-mass spectrometry. The antifungal efficacy of nanohexaconazole (N-hexa) was studied in vitro, compared with micronised hexaconazole (M-hexa) at different doses (5 ppm, 10 ppm and control) against two food pathogenic fungi: Aspergillus niger (MTCC 282, MTCC 2196 and BDS 113) and Aspergillus fumigatus through poisoned food technique. A dose-dependent significant growth inhibition was observed in nanohexaconazole (N-hexa) treated fungal sample compared with that of micronised hexaconazole (M-hexa). Micrographic studies for the morphological analysis of control and nanohexaconazole (N-hexa) treated fungal samples were done, exhibited an alternation in fungal morphology. Results showed that nanohexaconazole (N-hexa) is more efficacious than commercially available micronised hexaconazole (M-hexa). In future nanohexaconazole (N-hexa) could be a possible candidate for modern medical science and also reduce damage to the environment from injudicious use of pesticides.