Cohen syndrome is a rare, genetic, connective-tissue disorder, with the genetic abnormality linked to chromosome 8q22. Its physical features (particular facial characteristics; body, limb, and visual abnormalities; height and weight problems) have been well documented but little is known about the psychological and behavioural development of individuals with the condition. Suggestion of a dual diagnosis of autism in a small minority of individuals led to a more detailed survey of parents belonging to the Cohen Syndrome Support Group, based in the UK. Thirty-three individuals, 18 males and 15 females, aged from 2 to 45 years (mean age 15 years) were involved in the study. Over half of the participants (n=19) showed a pattern of impairments in social and communication skills, together with rigid and stereotyped behaviours or interests that seemed to meet DSM-IV/ICD-10 criteria for autism. ‘Autistic-type’ problems were as common in females as in males. In almost all cases, parents had noted difficulties in their child before the child reached the age of 1 year. This study suffers from a number of methodological shortcomings including the fact that it was a postal survey, the sample size was small, and no standardized diagnostic or psychometric data were available. However, the incidence of social, communication, and behavioural problems would seem to warrant further research and a larger-scale study is planned in association with an independent investigation of physical and genetic characteristics in the same group of individuals.