Three children with non-ketotic hyperglycinaemia (NKH) is reported. Two patients had typical neonatal form of NKH, one patients had atypical form of NKH. The clinical symptoms laboratory findings and therapeutical approach are discussed. One of the patients with typical neonatal form of NKH is died, neuropatological examination revealed corpus callosal agenesis and diffuse hypomyelinisation. The two children treated with N-methyl-D-aspartate-antagonist drugs reached a significantly better clinical condition. The authors reviewed the data of the literature, especially focused on the therapeutical possibilities.