Inefficient drug targeting continues to be a major problem that hamper effective treatment of chronic diseases like cancers. Clinically, anti-cancer drugs rely on the presence of enhanced permeability and retention (EPR) effect, provide less than 2-fold increases in delivery to tumor tissue compared with critical normal organs. Since monocytes are being recruited to the tumor site, it is believed these monocytes can act as carriers for anti-cancer drugs. Seven monocyte-targeting peptide liposomes (MMDCs) that consisted of different peptide sequence were developed, and were tested for their ability to anchor on the surfaces of human monocytes (THP-1). Microscopic images and flow cytometric analysis revealed Peptide-1 Liposomes could anchored on the surfaces of THP-1 for > 4 h at 37 ℃, and had no interaction with human endothelial cells (HUVEC). Conversely, the identified MMDCs could be internalized by the monocyte-derived macrophages. Our next step is to examine the targeting of Peptide-1 Liposomes for THP-1 in an in vitro perfusion system that mimic human vascular environment..