A detailed analysis of the occurrence of the C—H⋯O hydrogen bonds in sheet regions of proteins has been presented. 11 unique protein structures with resolution 1.3 Å containing β-sheets show a widespread presence of C—H⋯O hydrogen bonds. These have average Cα⋯O, CH⋯O distances and a Cα—H⋯O angle of 3.29, 2.38 Å and 143°, respectively. As in the case of N—H⋯O hydrogen bonds, parallel and antiparallel β-sheet regions show the same hydrogen-bond geometry. An inverse correlation is observed between the hydrogen-bond geometries involving the Cαi—H⋯O=C and the Ni+1—H⋯O=C suggesting that C—H⋯O hydrogen bonds may act as an additional stabilizing factor. The propensity of different amino-acid residues to form such hydrogen bonds varies and shows a clear preference for valine and threonine. C—H⋯O hydrogen bonds involving side chains also occur extensively in β-sheet regions.