The objective of this study was to determine the effect of nanopropolis to cure cancer induced on rat mammary tumor using 7,12-dimethylbenz(a)anthracene (DMBA). After the first tumors appearance, twenty eight rats were divided into seven groups. Group 1, 2 and 3 served as recipient of nanopropolis dosages 8, 32 and 56 µg/mL treatments; Group 4 served asrecipient of propolis dosage of 233 µg/mL treatment; Group 5 served asrecipient of doxorubicin treatment; Group 6 served as recipient of DMBA treatment and Group 7 as normal group (control). The effect of nanopropolis dosage of 32 µg/mL and propolis dosage of 233 µg/mL were similar in reducing tumor size, healing the wounds caused by the tumor and eliminating cancer cells. It turns out that there is a relationship between particle size absorbent materials. The study suggested that nanopropolis with small concentration was very effective to treatrat mammary gland tumors and breast cancers.