Macrocyclic oligomers (MCOs) are important as starting materials for Entropically-driven Ring-opening Polymerizations (ED-ROPs). This article reviews the preparation of MCOs by the cyclodepolymerization (CDP) of condensation polymers. Many MCOs have been prepared successfully this way and in numerous cases individual macrocycles have been isolated. This approach can provide one-step syntheses of many macrocycles. The combination of CDP plus ED-ROP is an attractive potential method for recycling ('Ringchain Recycling') many condensation polymers. (C) 2013 Elsevier Ltd. All rights reserved.