Objectives: The present study is designed to evaluate the antidiabetic activity of the ethanolic extract of the bark of Bischofia javanica (BJ) Blume (Euphorbiaceae). The study was conducted by using invivo alloxan induced diabetic model in wistar albino rats. The parameters that were used for the assessment of antidiabetic activity are liver glycogen and blood glucose levels. Materials and Methods: (Preparation of the Plant Extract): The leaves of the BJ were collected from Wayanadu, Kerala, India during October 2010 and was authenticated by Mr. Krishnan, Lecturer in Botany, Kannur University, Kerala. The collected barks were air dried. After that the barks were powdered in an electric grinder. The powdered plant bark was soaked in ethanol and kept aside for 7 days with occasional stirring. After 7 days, the ethanolic layer was filtered. The solvent from the total extract was distilled off and the concentrate was evaporated on a water bath to a syrupy consistency and then evaporated to dryness10. The yield obtained was approximately 9.5% (95g). The dried extract was then stored in a desiccator for further use. Expperimental Animals: Healthy adult Wistar albino rats, weighing about 180-220g between 2 and 3 months of age obtained from SCOP, Valachil, Mangalore were used for the study. The study was approved by the Institutional Ethics Committee for animal experimentation SCOP (Ref: SCP/CPCSEA/ P09/F150/2009-10), Valachil, Mangalore. Results and Conclusions: The study performed preliminary phytochemical analysis for testing different chemical constituents preent in ethanolic extract of the bark of BJ Blume and thereby the observations showed the presence of triterpinoids, saponins, and tannins. Furthermore, the results of the research indicate that the ethanolic extract of the bark reduces the blood glucose level in diabetic rats. Further studies are needed to isolate and characterize the active principles and to find out the mechanism responsible for its antidiabetic activity.