Pharmacological and preventive properties of Petroselinum sativum seed extracts are well known, but theanticancer activity of alcoholic extracts and oil of Petroselinum sativum seeds on human breast cancer cellshave not been explored so far. Therefore, the present study was designed to investigate the cytotoxic activitiesof these extracts against MCF-7 cells. Cells were exposed to 10 to 1000 μg/ml of alcoholic seed extract (PSA)and seed oil (PSO) of Petroselinum sativum for 24 h. Post-treatment, percent cell viability was studied by 3-(4,5-dimethylthiazol-2yl)-2, 5-biphenyl tetrazolium bromide (MTT) and neutral red uptake (NRU) assays, andcellular morphology by phase contrast inverted microscopy. The results showed that PSA and PSO significantlyreduced cell viability, and altered the cellular morphology of MCF-7 cells in a concentration dependent manner.Concentrations of 50 μg/ml and above of PSA and 100 μg/ml and above of PSO were found to be cytotoxic inMCF-7 cells. Cell viability at 50, 100, 250, 500 and 1000 μg/ml of PSA was recorded as 81%, 57%, 33%, 8%and 5%, respectively, whereas at 100, 250, 500, and 1000 μg/ml of PSO values were 90%, 78%, 62%, and 8%,respectively by MTT assay. MCF-7 cells exposed to 250, 500 and 1000 μg/ml of PSA and PSO lost their typicalmorphology and appeared smaller in size. The data revealed that the treatment with PSA and PSO of Petroselinumsativum induced cell death in MCF-7 cells.