An improvement in of deprotection in solid phase peptide synthesis is disclosed. The method includes the steps of adding the deprotection composition in high concentration and small volume to the mixture of the coupling solution, the growing peptide chain, and any excess activated amino acid from the preceding coupling cycle; and without any draining step between the coupling step of the previous cycle and the addition of the deprotection composition for the successive cycle; and with the coupling solution at a temperature of at least 30°C.
