Many of the cell adhesion receptors recognize simple sequences that can be reproduced as synthetic peptides. This circumstance has led to a widespread use of peptides as modulators of cell adhesion. Peptides capable of binding to cell adhesion receptors, such as the integrins, can be used as mediators of cell attachment to a surface by coating the surface with the peptide. Peptides bound to a solid phase can also be used to isolate adhesion receptors by affinity chromatography. Alternatively, the peptides can be used to inhibit cell attachment to the natural ligands of the adhesion receptors. In either mode, adhesion peptides have proven to be highly useful probes in cell adhesion research and they also show promise as a new class of therapeutics. The purpose of this article is to review some of the properties and uses of adhesion peptides.