Breast cancer is the leading cause of death, especially for women in Indonesia. Compounds that are widely used for anticancer at present are organotin compounds, one of which is dithiocarbamate compounds, with several reports of antifungal, antibacterial, anticancer, anti-alkylation, and apoptosis-inducing activities of metal dithiocarbamate complexes and their mixed ligands. The purpose of this study was to determine the activity test of the synthetic compound Diphenyltin (IV) N-Benzylmethyldithiocarbamate Against Breast Cancer MCF-7 using the MTT Assay (Microculture Tetrazolium Technique) Assay and to determine the functional group and structure of the compound Dibutyltin (IV) N-Benzylmethylditiocarbamate, used Spectrophotometer test FTIR (Fourier Transformed Infrared) and FTNMR (Nuclear Magnetic Resonance). From this study, it was found that the synthetic compound Diphenyltin (IV) N-Benzylmethyldithiocarbamate is a very potent compound in inhibiting the development and growth of MCF-7 breast cancer cells, because the compound has an IC50 value that is smaller than 10 g/ml which is 69, 640ppm.