This paper presents contemporary opinions about selective mutism in children, including epidemiology, etiology, clinical features and therapy. This is the first extensive review on this topic in Polish literature. The essential feature of selective mutism is persistent failure to speak in social situations, where speaking is expected (e.g., in school), despite speaking in other situations (e.g., at home). The authors present the diagnostic criteria according do DSM-IV and suggested by other authors. Clinical characteristics of this disorder were also presented, including personality traits and behaviour of mutistic children (different at home and in unfamiliar environment) and comorbidity of selective mutism. Etiology of this disorder seems to be multifactorial. The important etiological factors are: minimal brain dysfunction, somatic or psychological trauma, particularly during the speech development and a family structure, especially the mother-child relation. The authors emphasize that mutism in children is a heterogeneous symptom and present several models of mutism. The paper describes also different methods of treatment (e.g., behavioral, psychodynamic, family therapy and some case reports on pharmacotherapy); and long-term prognosis.