CD30, a member of the tumor necrosis factor receptor superfamily, is a transmembrane glycoprotein receptor consisting of an extracellular domain, a transmembrane domain, and an intracellular domain. CD30 has emerged as an important molecule in the field of targeted therapy because its expression is generally restricted to specific disease types and states. The major cancers with elevated CD30 expression include Hodgkin lymphoma and anaplastic large T-cell lymphoma, and CD30 expression is considered essential to the differential diagnosis of these malignancies. Most commonly, CD30 expression is detected and performed by immunohistochemical staining of biopsy samples. Alternatively, flow cytometry analysis has also been developed for fresh tissue and cell aspiration specimens, including peripheral blood and bone marrow aspirate. Over the past several years, several therapeutic agents were developed to target CD30, with varying success in clinical trials. A major advance in the targeting of CD30 was seen with the development of the antibody-drug conjugate brentuximab vedotin, which consists of the naked anti-CD30 antibody SGN-30 conjugated to the synthetic antitubulin agent monomethyl auristatin E. In 2011, brentuximab vedotin was approved by the US Food and Drug Administration for use in Hodgkin lymphoma and anaplastic large cell lymphoma based on clinical trial data showing high response rates in these indications. Ongoing trials are examining brentuximab vedotin after autologous stem cell transplantation, as part of chemotherapy combination regimens, and in other CD30-expressing malignancies, including primary mediastinal large B-cell lymphomas, diffuse large B-cell lymphoma, lymphoma positive for Epstein-Barr virus, peripheral T-cell lymphoma not otherwise specified, and cutaneous anaplastic large cell lymphoma.