The purpose of this study was to elucidate anxiety symptoms (hereafter referred to as “signs") observed in the growth process of brothers and sisters of handicapped children (hereafter referred to as “siblings"), their cause, and the special attention of the mother in bringing up the siblings by interviewing handicapped children's mothers and “siblings". The results of the investigation revealed that 12 of 32 siblings of handicapped children brought up by 20 mothers showed some signs, and 10 of 12 siblings showed certain characteristics, whose causes were related to their handicapped brethren. The causes comprised the following factors : “mother's absence or increased strain in a family due to hospital attendance for the handicapped child" ; “preoccupation of the mother with the handicapped child; as a result of which childcare for the siblings became insufficient" ; “siblings bear the role of helping the handicapped children and cannot easily take an initiative for themselves ", and “conflict produced by how their friends treat the handicapped children." The special attention of the mother in bringing up the siblings is classified roughly into two categories: “communicating consciously with the siblings" and “taking care to maintain a smooth relationship between the handicapped child and the siblings." The following subjects are inferred to be effective as advice to mothers who are bringing up handicapped child and siblings: “allocate time for spending exclusively with the siblings" and “take care that the siblings understand and respect brethren who are handicapped." Moreover, cases of special difficulty were observed in relation to handicapped brethren: even if a mother takes care to treat the handicapped child and siblings equally, the mother's attention inevitably tends toward the handicapped child; alternatively, there is sometimes a gap in the concepts of equality between the mother and the siblings. Delicate care is suggested according to each case considering the order of the siblings and the potential of the handicapped child. In this study, “siblings" denotes handicapped children's sibship, while “brethren" denotes handicapped children.