Breast cancer is a genetic disease due to the accumulation of genetic abnormalities in tissues. There are cell proteins that can reduce the growth of cancer cells. Bax and Bcl-2 are proteins that accelerate the process of apoptosis of cancer cells and maintain the permeability of mitochondrial cell membranes and cytotoxic activation of caspase so as to prevent the spread and development of cancer cells. The purpose of this study was to determine the effect of pare ethanol extract on the expression of Bax and Bcl-2 in T47D cell cultures. This research uses experimental in vitro with the Post Test Only Control Group Design method. The subjects of this study were T47D cells divided into 4 treatments with three replications on the variables. The treatment consisted of negative control, positive control, pare ethanol extract 1/2 IC50 (134.7 g/mL), 1 IC50 (269.4 g/mL) and 2 IC50 (538.8 g/mL). On the 10th day, an examination of Bax and Bcl-2 expressions was carried out. The data were analyzed using the Anova One Way Test. One Way Anova test result showed the results of Bax protein expression and BCL-2 expression in all groups there was a significant difference (p< .05). The administration of pare ethanol extract at dose of 2 IC50, 1 IC50, and 1/2 IC50 showed a significantly affect to increase of Bax protein expression in T47D breast cancer cells.