Medicinal plants have been used for treatments of various diseases and still play an important role to cover the basic health needs in the developing countries. In this study, phytochemical screening, determination of total phenolic and flavonoid content, antioxidant and antibacterial activity of the stem bark of Clematis simensis [known by its vernacular name as “azohareg” (in Amharic)], is reported. Thus the successive extraction by using petroleum ether, chloroform and ethanol result in 0.4 %, 0.7%, and 0.9% crude extract yield respectively. The phytochemical screening of crude extracts showed the presence of flavonoid and steroid in all solvent extract, terpenoid and cardiac glycoside in chloroform extract, phenolics in ethanol extract, and tannin in ethanol and chloroform extract. The total flavonoid and phenolic content of ethanol extract is higher than chloroform and petroleum ether extracts. This could lead to potential biological activity of the plant extract. The antioxidant and antibacterial activity against two Gram positive bacteria (Staphylococcus aureus and Streptococcus pyogenes and two Gram negative bacteria, Escherichia coli and Klebsiella pneumonia) of ethanol extract is higher than chloroform and petroleum extracts as well as isolated fractions, F1 and F2.