XPS is used to study the binding energy of the Cls, Nls and Ols photoelectrons of surface groups on several nitrogen-containing activated carbons. Specific binding energies are assigned to amide (399.9 eV). lactam and imidc (399.7 eV). pyridine (398.7 eV), pyrrole (400.7 eV), alkylamine. secondary amide and N-alkylimide (399.9 eV) and trialkylaminc (399.7 cV) functional groups on activated carbon. Supporting evidence is obtained for our hypothesis that the modification method governs the type of nitrogen function formed: ammoxidation leading to amides, animation to lactams and imides and further heat treatment to pyridine and pyrrole groups. Moreover, the XPS results confirm the attachment of tertiary amine groups to the carbon surface by reaction of pre-oxidized carbons with organic amines through ester and secondary amide or N-alkylimide spacing groups.