This study described the beneficial properties of ultrasonic irradiation approach to synthesize the spinel-type DyY co-substituted Mn-Zn nanospinel ferrites (NSFs). We have used two different approaches like citrate sol-gel combustion and ultrasonic irradiation routes to produced series of Mn0.5Zn0.5Fe2-2x(DyxYx)O-4 (0.0 <= x <= 0.05) NSFs (DyY-MnZn NSFs). The structure and morphology of NSFs X-was examined by using XRD, EDX, SEM and TEM methods. We have found that spinel ferrites and hematite phase in DyY-MnZn NSFs produced by citrate sol-gel, while DyY-MnZn NSFs created by ultrasonic irradiation contain a pure phase of spinel ferrite. TEM analysis revealed the spherical nanoparticles with fairly uniform size. We have also analyzed the biological applications of DyY-MnZn NSFs prepared by both methods (ultrasonication and sol-gel) by examining their anti-cancer and anti-bacterial (Escherichia coli and Staphylococcus aureu) activities. We have found that both methods produced inhibitory actions on colon cancer cells (HCT-116) and bacterial cells, whereas, no inhibitory action was observed when examined on normal and non-cancerous cells (HEK-293).