Schizophrenia, a most prevalent brain disorder, remains to be one of the least understood. Unlike Alzheimer's disease or Parkinson's disease, schizophrenia lacks clear pathological lesions, which has made it difficult to model in animals. However, genetic studies have recently identified many susceptibility genes of this disorder including neuregulin 1 (NRG1) and its receptor ErbB4. Arguably, relevant mutant mice have provided a unique opportunity to model "schizophrenia" in animals where expression or function of susceptibility genes is altered. This review summarizes recent studies of NRG1 and ErbB4 mutant mice and their implication in schizophrenic pathology.