Cancer patients with malignant involvement of tumor-draining lymph nodes (TDLNs) and distant metastases have the poorest prognosis. A drug delivery platform that targets the primary tumor, TDLNs, and metastatic niches simultaneously, remains to be developed. Here, we generated a novel monoclonal antibody (MHA112) against peripheral node addressin (PNAd), a family of glycoproteins expressed on high endothelial venules (HEVs), which are present constitutively in the lymph nodes (LNs) and formed ectopically in the tumor stroma. MHA112 was endocytosed by PNAd-expressing cells, where it passed through the lysosomes. MHA112 conjugated antineoplastic drug Paclitaxel (Taxol) (MHA112-Taxol) delivered Taxol effectively to the HEV-containing tumors, TDLNs, and metastatic lesions. MHA112-Taxol treatment significantly reduced primary tumor size as well as metastatic lesions in a number of mouse and human tumor xenografts tested. These data indicate that human metastatic lesions contain HEVs and provide a platform that permits simultaneous targeted delivery of antineoplastic drugs to the three key sites of primary tumor, TDLNs, and metastases.