1. Adhesion is a vital property of cells. It provides a stable environment for cell growth and differentiation and allows cells to migrate. 2. The interaction between cells and their extracellular matrices is also an important factor in the regulation of further protein deposition. Likewise, matrix proteins can influence cellular function thus creating a complex feedback mechanism. 3. The adherence of cells to each other, their extracellular matrices and endothelial surfaces is mediated by a variety of membrane proteins collectively known as adhesion molecules. 4. Adhesion molecules can be further divided into four subfamilies: the integrins, the selectins, the cadherins and the immunoglobulin superfamily. This article will review our current knowledge of the integrin family of adhesion receptors, focusing principally on their role in the pathogenesis of human disease.