Onychomycosis is a widely distributed fungal nail infection which can be caused by dermatophytes, yeasts or non-dermatophytic fungi.  In our study a total of 7 species related to 4 genera were isolated from 50 patients suspected with the fungal nail infection (onychomycosis) these namely Aspergillus flavus (8 isolates), Aspergillus niger (13 isolates), Candida albicans (8 isolates), C. tropicalis (5 isolates), Epidermophyton floccosum (1 isolate), Trichophyton mentagrophytes (2 isolates) and Trichophyton rubrum (1 isolate). Nowadays the field of nanotechnology becomes one of the most topics of interest. The impact of gold nanoparticles on the isolated fungal species was evaluated by agar well diffusion method and micro-dilution method. Best antifungal activity of gold nanoparticles was observed by using 100 µl of AuNps containing 20 µg of gold nanoparticles with the greatest zone of inhibition (19 mm) against C. albicans. AuNps showed variable MIC (minimum inhibitory concentration). MIC₅₀ and MIC₉₀ values of AuNPs ranged from 3.125 to 25.0 μg/ml and from 12.5 to100 μg/ml respectively. All isolated fungi could grow on keratin agar medium but with variable degrees indicating their ability to hydrolyze keratin. Keratinase activity in presence and absence of AuNPs was determined for dermatophytes and Aspergillus species. AuNPs had an inhibitory effect causing reduction in keratinase enzyme activity reaching 52.17 %, 40 % and 37.5 % was attained in case of E. floccosum, A. flavus and A. niger (the most susceptible isolates) respectively, by application of 20 µg/ml of AuNPs.