Peptide synthesis on cellulose using the SPOT technology follows the standard Fmoc-chemistry and can be performed manually or automated. This method allows the synthesis of low-cost peptide arrays containing around 900 large spots of addressable peptides on a cellulose sheet of 19 cm x 29 cm. These peptides can be cleaved from the cellulose support by ammonia gas and afterward spotted on glass microchips. Alternatively, the peptides can be synthesized on modified cellulose discs and CelluSpot microarrays can be produced.