We describe here a simple modification of the HN(C)N experiment for the generation of serine/threonine check points in the three-dimensional experiment. The various `triplet of residue’ specific peak patterns in the spectra are documented for ease of analysis and sequential backbone resonance assignment. The performance of this experiment, referred to as HN(C)N-ST, is demonstrated using two proteins, one properly folded and the other completely denatured. It is noteworthy that, even in the denatured protein, where spectral dispersions are rather poor, about 90% of the sequential connectivities through the chain could be established from this single experiment. This would have great implications for structural genomics efforts.