Methotrexate (MTX) is being used in clinical oncology for the treatment of a wide variety of cancers. The aim of the present study was to label directly MTX with (99m)Tc by using Sn/pyrophosphate as reducing agent and to use this labeled compound as a potential anticancer radiopharmaceutical for breast cancer imaging. We studied the labeling efficiency of the (99m)Tc-MTX compound by paper chromatography and instant thin layer chromatography (ITLC) in acetone and saline and found it to be more than 95%. In vitro stability of labeled MTX in serum was studied up to 5h. Partition coefficient in n-octanol and saline indicated that the labeled radiopharmaceutical was hydrophilic. We then tested (99m)Tc-MTX in 5 breast cancer female patients. Protein bound (99m)Tc-MTX showed rapid clearance from blood. The biodistibution data suggested that (99m)Tc-MTX was cleared by the kidneys and the liver. Patients ' data also showed highly significant uptake of (99m)Tc-MTX in breast cancer. In conclusion, this study indicated that (99m)Tc-MTX may be used as a potential diagnostic agent for breast cancer patients imaging and may show treatment efficiency in case MTX is to be used for treatment.