Kelussia odoratissima Mozaff. (common Iranian name: Karafs-e-koohi, Wild celery) belonging to Apiaceae family is an indigenous and ethnomedicinal plant, which grows in restricted area of the Zagros ranges at high elevation of 2500 m in Iran. 3-butylidene-4,5-dihydrophthalide (z-Ligustilide) and 3-e-butyl phthalide, hitherto have been found as its major chemical composition (Rabbani et al., 2011). Likewise K. odoratissima, Z-Ligustilide and n-butylidenephthalide were reported as the main bioactive components of Angelica sinensis root extract. Researchers announced that A. sinensis extract induced apoptosis and led to cell cycle arrest at G0/G1 in brain tumor cell lines. n-butylidenephthalide and Z-ligustilide were cytotoxic against brain tumor cell lines, leukemia cells and colon cancer HT-29 cells (Chao and Lin, 2011). The present investigation was carried out to study the anticancer effects of different crude extracts of K. odoratissima leaves against different kinds of human tumor cell lines.Materials and Methods A549, MDA-MB 468, MCF7, Hela, k562 and 2 others cell lines were separately cultured in RPMI-1640 medium completed with 10% fetal calf serum and penicillin / streptomycin (50 IU/ml and 50 μg/ ml respectively). Collected leaves were dried and powdered, then were soaked in five solvents with different lipophilicity. The cytotoxic effects of different concentration of crude extracts on cultured cells were measured using the MTT assay. SPSS 16.0 software was used to perform statistical analysis. Three independent experiments were examined as the mean values ± standard mean deviation (SD). Analyze-of-variance (ANOVA) followed by LSD test (as the Post-Hoc) was used to assess significance between the test sample and solvent control. P-value< 0.05 was considered to be statistically significant.Results and Discussion Methanolic extract exerted higher anti-cancer activity in different kinds of cancer cells compared with other extracts. Furthermore, methanol extract induced a significant growth inhibition and apoptosis in a dose-dependent manner on all cancer cell lines. The present results suggest that valuable cytotoxic components could be isolated from this plant by partitioning methanol crude extract. Further investigations are underway in this regard.