Aim: The authors report the biological synthesis of zinc oxide nanoparticles (ZnO-NPs) from the petals extract of Rosa indica L. (rose). Its efficacy was evaluated against two dermatophytes: namely: Trichophyton mentagrophytes and Microsporum canis which cause onychomycosis. The activity of antibiotics against the tested dermatophytes was enhanced, when evaluated in combination with ZnO-NPs. Methods and results: The synthesised ZnO-NPs were preliminary detected by using ultraviolet UV visible spectroscopy, which showed specific absorbance. The ZnO-NPs were further characterised by nanoparticle tracking analysis (NTA), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray diffraction and Zetasizer. Moreover, nanoparticles containing nail paint (nanopaint) was formulated and its antifungal activity was also assessed against T. mentagrophytes and M. canis. ZnO-NPs and formulated nanopaint containing ZnO-NPs, both showed significant antifungal activity. The maximum activity was noted against M. canis and lesser against T. mentagrophytes. Minimum inhibitory concentration of ZnO-NPs was also determined against the dermatophytes causing onychomycosis infection. Conclusion: ZnO-NPs can be utilised as a potential antifungal agent for the treatment of onychomycosis after more experimental trials.