Abstract Several methods are presented for the selective determination of spin–lattice and spin–spin relaxation rates of backbone protons in labeled proteins. The relaxation rates of amide protons in 15N labeled proteins can be measured by using two-way selective cross-polarization (SCP). The measurement of H α relaxation rates can be achieved by combining this method with homonuclear Hartmann–Hahn transfer using doubly selective irradiation. Various schemes for selective or nonselective inversion of the longitudinal proton magnetization lead to different initial recovery rates. The methods have been applied to lysine K6 in 15N-labeled human ubiquitin and to leucine L5 in 15N- and 13C-labeled octapeptide YG*G*F*LRRI (GFL) in which the marked residues are 15N- and 13C-labeled.