Dental enamel is the most mineralized tissue in the vertebrate body and contains the largest known biologically formed hydroxyapatite crystals. Its formation occurs extracellularly through the collaborationof a proteic transient framework (the enamel organic matrix), which controls hydroxyapatite crystal growth, morphology and orientation. This matrix is deposited with a small amount of mineral during the secretory stage of amelogenesis. The organic components begin to bedegraded in the transition stage and are extensively corrupted, and almost entirely replaced by the inorganic crystallites during maturation stage. The present paper reviews current knowledge on the structural biology of the enamel organic matrix