Cancer is one of the leading causes of death in the world. One of the therapies for cancer is 5-FU, but the effectiveness of 5-FU as a chemotherapy agent is still low so combination agents are needed to increase its effectiveness. Rosuvastatin tablets have been studied to reduce the viability of melanoma cells. Besides that rosuvastatin has also been reported to reduce cell proliferation, colony formation and invasive potential in prostate cancer cells. This study aims to determine the combination cytotoxic effect of rosuvastatin and 5-FU on T47D breast cancer cells, determine the effectiveness of the combination of rosuvastatin and 5-FU on inhibition of proliferative kinetics of T47D breast cancer cells. Cytotoxic tests were carried out using the MTT assay method with an incubation time of 24 hours. The rosuvastatin cytotoxic test showed potential cytotoxicity with IC50 of 26.26943 μg / mL. The combination of rosuvastatin and 5FU with various variations of concentration gave a strong synergistic effect (CI <0.3) to the antagonistic effect (CI> 1.1). T47D cells decreased the number of cells at 24 to 72 hours in treated cells compared with cell control, the combination of rosuvastatin and 5-Fluorouracil can increase 5-Fluorouracil sensitivity so that it can inhibit greater T47D cell proliferation compared to rosuvastatin tablet treatment and 5 Single fluorouracil.