Integrins are a large family of molecules that are central regulators in multicellular biology. They orchestrate cell–cell and cell–extracellular matrix (ECM) adhesive interactions from embryonic development to mature tissue function. Diverse human pathologies involve integrin adhesion, including thrombotic diseases, inflammation, cancer, fibrosis and infectious diseases. Integrins are exciting pharmacological targets because they are exposed on the cell surface and are sensitive to pharmacological blockade, but the scale of current efforts involving integrin therapeutics continues to surprise. Several therapeutics targeting integrins are effective drugs: five have been approved for use in clinic, with combined sales of over $1.5 billion in 2010 (based on company reports from that year). We gathered information from three major drug-trial databases and found that ∼260 anti-integrin drugs have entered clinical trials. Here we overview integrins as drug targets and focus on cancer.