Encapsulation of cell cultures is a universally applicable tool in cell culture technology. Basically it can be used to protect cells against hazardous environmental conditions as well as the environment against disadvantageous effects triggered by the immobilized cultures. The three basic encapsulation systems, described here, are the bead, the coated bead, and the membrane-coated hollow sphere. Another two universally applicable methods to quantify the number of living cells immobilized in those encapsulation systems could be used.