Medicinal plants constitute an important component of flora and are widely distributed in Sudan. The pharmacological evaluation of substrates from plant s is an established method for the identification o f compounds, which can lead to the development of novel and safe medicinal agents. Based of the ethno pharmacologic al literature, several species of medicinal plants use d in traditional medicine in Sudan were collected. In the present study, ethanolic extracts of some medicinal plants were screened for their cytotoxicity using brine sh rimp lethality test. Out of the 25 plants tested, Azadrichta indic a (w.p.) LC50 45 ppm, (L) LC50 21; Aristolochia bra cteolata(w.p.) with LC50. 50 ppm; (Sd.) LC50 185; (Aristolochic ac id, LC50 19 ppm; while Savadoora persica,(L.), (Salvadoraceae) and Ocimum basilicum; (Labiatae); show no toxicity. The present study supports the pr evious that brine shrimp bioassay is simple, reliable, and conv enient method for assessment of bioactivity of medi cinal plants and leads support for their use in traditional medi cine 1 .