Linear single oligomers of nylon-6, up to 12 repeat units, have been prepared by stepwise synthesis using protection, deprotection, and coupling reactions. The dimer was synthesized starting with 6-aminohexanoic acid; the tetramer, hexamer, octamer, and dodecamer were synthesized by coupling oligomers of lower molecular weight. The synthesized oligomers were characterized by 1H NMR and TOF-SIMS to confirm their structures and molecular weights. In addition to silver cationized oligomer peaks, which are usually observed in TOF-SIMS spectra, oligomer peaks cationized by sodium and hydrogen were observed. No fragmentation other than loss of H2 was observed even for the highest oligomer prepared in this study.