Psychometric properties of the Diagnostic Interview for Social and Communication Disorders schedule (DISCO) have only been studied in the UK. The authorised Swedish translation of the tenth version of the DISCO (DISCO-10) was used in interviews with close relatives of 91 Swedish patients referred for neuropsychiatrical assessment. Validity analysis compared DISCO-10-algorithm diagnoses with clinical diagnoses and with Autism Diagnostic Interview Revised (ADI-R) algorithm diagnoses in 57 cases. Good-excellent inter-rater reliability was demonstrated in 40 cases of children and adults. The criterion validity was excellent when compared with clinical diagnoses and an investigator-based diagnostic interview. The DISCO-10 has good psychometric properties. Advantages over the ADI-R include valuable information of the broader autism phenotype and co-existing problems for clinical practice and research.