Diabetes Mellitus (DM) is a disease associated with severe derangement of carbohydrates, protein and lipids metabolism. The growing global incidence of diabetes mellitus in adults as well as young people continues to challenge the health sector, especially the Type-2 DM. Management of DM via the orthodox means continues to struggle globally due to increasing human population, poverty and gene modifications from inter-racial marriages. In local settings, plants with purported antidiabetic characteristics have been employed over time in managing DM. And is on this basis that this research was carried out to investigate the plant; Nephrolepis undulate. Fresh leaves of Nephrolepis undulate (NU) collected washed, air-dried and grounded and soaked in methanol for 48 hours. The mixture was filtered and the extract gotten was subjected to liquid-liquid fractionation using (Chloroform, Ethyl acetate, and n-hexane), allowed and used for the treatment at a dose of 250mg/kgbw. Metformin was administered at 50mg/kgbw. DM was induced with STZ at a dose of 60mg/kgbw. At the end of the treatment period (21 days), the rats were sacrificed and blood and tissue samples collected. All analysis was conducted using documented standard methods. Research findings showed a significant reduction in serum glucose concentration following treatment with NU, a decrease in the elevated level of MDA and an increase in the depressed levels of SOD and Catalase. The conclusion is that NU possesses both anti-diabetic and antioxidant properties. The mechanism of action could be its inhibitory effect on glucose hydrolyzing enzymes and its ability to facilitate cellular detoxification.