We give a review of the maturation and aging processes of elastic fibers. Elastic fibers of adult human skin are composed of elastin (amorphous matrix) and surrounded by microfibrils (structural glycoproteins). The physiological aging of elastic fibers is a continuous process starting at the age of 40 or 50 and reaching its final state in the senium. This process is characterized by the following morphological changes: (1) decreasing number of microfibrils, (2) occurrence of osmiophilic inclusions, and (3) fragmentation and disintegration of the fibers. These alterations are due to reduced synthesis of elastin and increased deposits of lipids and calcium. As a result, the elastic fibres show increased susceptibility towards proteolytic enzymes.