The application of capillary isotachophoresis (CITP) and combined CITP-mass spectrometry (MS) for peptides and proteins is demonstrated. Separation of simple peptide mixtures, as well as enzymatic digets of proteins, is also reported using CITP with UV detection. The potential utility of CITP for proteins is demonstrated. Initial studies of combined CITP-MS of enzymatic digests is also demonstrated, showing the potential for rapid sequence determination.