A method of recycling fusible polycondensation resin waste in a fusion polymerization apparatus is disclosed. The method of recycling polycondensation resins comprises adding polycondensation resin waste directly to a fusion polymerization apparatus to carry out the polycondensation reaction. The polycondensation resin waste may be supplied from any point of the polycondensation apparatus to carry out the exchange reaction and/or the polycondensation reaction between the resin being prepared in the apparatus and the resin waste supplied. The method may be carried out in a continuous fusion polycondensation system with more than one polymerization reactor connected in series. The polycondensation resin waste may be supplied from the outlet of a polymerization reactor during the initial stage of the polycondensation process (oligomerisation process) to carry out the exchange reaction and/or the polycondensation reaction between the resin waste and the resin being prepared in the later stage of the polycondensation process in a continuous fusion polycondensation apparatus with more than one polymerization reactor connected in series.