Eighteen children (13 males, five females) who had severe developmental language delay/disorder and some features of autism (although insufficient in severity and combination to meet ICD-10 diagnostic criteria for childhood autism) at preschool age (Time 1; mean age 4 years 4 months) were followed up 4 years later (Time 2; mean age 8 years 7 months). At the initial assessment the diagnostic dilemma was how much the social communication impairments and behavioural problems were secondary to the language problem and how much they constituted a genuine case of a pervasive developmental disorder. It was anticipated that at follow-up some children would continue to show social impairments but that in others social impairments would have receded as language competence improved. Follow-up assessments included the Wechsler Intelligence Scale for Children, the Clinical Evaluation of Language Fundamentals, the Children's Communication Checklist, and the Social Communication Questionnaire. At follow-up, five children had continuing language disorder and were considered to fulfil diagnostic criteria for childhood autism, four children had continuing language disorder and met criteria for atypical autism, and nine met criteria for atypical autism but had somewhat recovered language skills. Thus, even in the subgroup of children whose language ability had improved the features of autism had not dissipated. Severity of social communication impairments and repetitive behaviours at Time 1, rated retrospectively from case notes, were associated with severity of autism symptoms and pragmatic competence at Time 2. The findings are discussed in relation to the unclear boundary between autism spectrum disorders and language delay/disorder.