A set of representative hydrogen bonded dimers has been studied employing density functional theory (DFT) in the Perdew, Burke, and Ernzerhof (PBE) generalized gradient approximation. Our results for hydrogen bond (hb) strengths and geometry parameters show good agreement with those obtained by Moller-Plesset (MP2) or Coupled-Cluster (CC) methods. We observe that the reliability of DFT-PBE for the description of hbs is closely connected to the bond directionality (i.e. the angle between D-H and H(...)A where D and A are the donor and the acceptor atoms or regions, respectively, in the hb interaction): with increasing deviation from a linear D-H(...)A arrangement the accuracy of the DFT-PBE decreases.