In this study, anti-proliferative and apoptotic effects of paclitaxel, which is itself an anti-chemotherapeutic agent, to FM3A cell line originated from Mouse mammary carcinoma at 7 different doses were examined. Seven different doses of paclitaxel (P1 = 3 nM, P2 = 7.5 nM, P3 = 15 nM, P4 = 30 nM, P5 = 60 nM, P6 = 120 nM, P7 = 240 nM) were administered to cells for 24 and 48 h. Growth rate measurements showed that living cell number decreased and number of dead cells increased (p<0.05). Acquired growing rates were supported by mitochondrial dehydrogenase enzyme activity. Loss of volume, protrusions at plasma mebrane (bleb formations), nuclear condensations and fragmentations, and apoptotic body formations were observed in cells whose morphologic criteria were examined by phase contrast and fluorescent microscope. According to apoptotic index rates determined by DAPI, most intense apoptotic cell formations were observed for P2 dose, which is accepted as critical for this cell line. DNA fragmentations were shown by agarose gel electrophoresis method. Acquired deductions showed that of the seven different doses of paclitaxel, P2 (7.5 nM) was the best dose to induce apoptosis in FM3A cells for 24 and 48 h.