Emotional and behavioural problems and competencies in a nation-wide sample of referred selective mute children (SM) and matched non-referred controls, aged 4-16 years, were assessed by the Child Behaviour Checklist, (CBCL), Teacher Report Form (TRF) and Youth Self Report (YSR) (1). Main issues addressed were the co-variation of internalising and externalising problems reported across informants, whether there exists a pure externalising group of children with SM, and the nature of the internalising and externalising problems. The results show that the children with SM differed substantially from their peers in internalising problems as reported by the parents and the teachers. In contrast, the results on the YSR indicated an under-reporting of internalising problems. Externalising problems in SM were reported in a low to moderate degree by the parents only. No child with SM and pure externalising symptoms was found. The children with SM differed mostly from their peers on the withdrawn scale. On the item level, both the internalising and the externalising symptoms that best differentiated the children with SM from the controls support the notion of SM as an expression of social anxiety.