Hepatocyte Growth Factor (HGF) specifically binds the c‐Met receptor by forming a homodimer from two heterodimeric molecules. HGF binding to c‐Met results in a multifunctional signaling cascade that activates the upregulation of cellular proliferation under normal conditions. HGF is overexpressed in many types of cancers and increased activity of the HGF:c‐Met pathway causes tumorigenesis and metastasis. We sought to generate an aptamer to HGF that would inhibit the functional interaction between HGF and c‐Met.Aptamers are oligonucleotides that fold into three‐dimensional structures and specifically bind to ligands with high affinity. Aptamers bound to proteins can modify and/or inhibit protein‐protein interactions. Through Systematic Evolution of Ligands by EXponential enrichment (SELEX), an anti‐HGF aptamer that inhibits the HGF:c‐Met pathway was generated from a modified RNA pool. A systematic analysis was carried out to identify the aptamer's smallest functional core and to further optimize the aptamer, resulting in a high affinity, nuclease‐resistant aptamer. Addition of a polyethylene glycol moiety allows for use of aptamer in vivo. The resulting aptamer inhibits cell mobility in a cell scatter assay and reduces tumor growth in the tumor model. These results demonstrate that the anti‐HGF aptamer inhibits tumor proliferation and has the potential to be used as a cancer therapeutic.