In biomolecules, bifurcated H-bonds typically involve the interaction of two donor protons with the two lone pairs of oxygen. Here, we present direct NMR evidence for a bifurcated H-bonding arrangement involving nitrogen as the acceptor atom. Specifically, the H-bond network comprises the Nd1 atom of histidine and both the backbone N-H and side-chain O gamma-H of threonine within the conserved TXXH motif of ankyrin repeat (AR) proteins. Identification of the H-bonding partners is achieved via solution NMR H-bond scalar coupling (HBC) and H/D isotope shift experiments. Quantitative determination of (2h)J(NN) HBCs supports that Thr N-H center dot center dot center dot Nd1 His H-bonds within internal repeats are stronger (similar to 4 Hz) than in the solvent exposed C-terminal AR (similar to 2 Hz). In agreement, pK(a) values for the buried histidines bridging internal ARs are several units lower than those of the C-terminus. Quantum chemical calculations show that the relevant (2h)J and (1h)J couplings are dominated by the Fermi contact interaction. Finally, a Thr-to-Val replacement, which eliminates the Thr O gamma-H center dot center dot center dot Nd1 His H-bond and decreases protein stability, results in a 25% increase in (2h)J(NN), attributed to optimization of the Val N-H center dot center dot center dot Nd1 His H-bond. Overall, the results provide new insights into the H-bonding properties of histidine, a refined structural rationalization for the folding cooperativity of AR proteins, and a challenging benchmark for the calculation of HBCs.