This study was designed to investigate the family environment and the temperament of children with Down's syndrome (DS). Parents of 40 children with DS completed the Family Environmental Scale (FES). They also were asked to fill out the Temperament Assessment Battery for Children (TABC) for both the child with DS and the nearest same-sex sibling. A similar questionnaire of the TABC (teacher form) was sent to the children's teachers. The results of these investigations revealed that there were high scores in categories cohesion, expressiveness, achievement, moral/religious emphasis, organization and control on the FES, indicating that family members in the study cohort are relationship oriented, provide support for one another, emphasize ethical values and are able to express their feelings. Comparing TABC results between children with DS with their siblings, significant differences were observed in such categories as adaptability, approach/withdrawal and persistence. Control children were scoring higher in the adaptability and persistence categories, whereas children with DS achieved significantly higher scores than the control children in the approach/withdrawal category.