The application of metal oxide nanoparticles, particularly zinc oxide, in medicine is essential, especially due to their physical and chemical characteristics and their antifungal potential. By the biological method, the zinc oxide nanoparticles were synthesized. This study aimed to investigate the in vitro activity generated by zinc oxide nanoparticles using a biological technique against Candida albicans in leukemia patients. The zinc oxide nanoparticles underwent characterization using Fourier transform infrared spectroscopy and XRD. The ability of the synthesized nanoparticles to inhibit human Candida albicans isolated from leukemia patients could be achieved by the Sabouraud Dextrose Agar method and differentiated using CHROM candida agar, germ tube test, and API Candida albicans. The antifungal activity of zinc oxide was investigated against Candida albicans. After assessing its susceptibility to several types of fungal antibiotics, thirty-three samples of Candida albicans developed resistance to fungal activity. Candida albicans inhibition zone diameters were 11, 12, 12, and 10 mm at zinc oxide nanoparticle concentrations of 400, 200, 100, and 50 mg/ml, respectively, while no inhibition zones occurred at low values of 25 mg/ml.