NMR pulse sequences for measuring coupling constants in C-13,N-15-labeled proteins are presented. These pulse sequences represent improvements over earlier experiments with respect to resolution and number of radiofrequency pulses. The experiments are useful for measuring J(NH)beta, J(NCO), J(NC)alpha, J(H)N(CO) and J(H)N(H)alpha. Applications to chymotrypsin inhibitor 2 (CI-2) are shown.