. In this meta-analysis of 34 clinical studies on attachment the hypothesis is tested that maternal problems such äs mental illness lead to more deviating attachment classification distributions than child Problems such äs deafness. A correspondence analysis on 21 North American studies with normal subjects produced a baseline against which the clinical samples could be evaluated. Separate analyses were carried out on studies containing the traditional A, B, C classifications and on studies that also included the recently discovered D or A/C category. Results show that groups with a primary identification of maternal problems show attachment classiflcation distributions highly divergent from the normal distributions, whereas groups with a primary identification of child problems show distributions that are similar to the distributions of normal samples. The introduction of the D or A/C classifications (about 15% in normal samples) reveals an overrepresentation of D or A/C in the child problem groups, but the resulting distribution still is much closer to the normal distributions compared to the samples with maternal problems. In clinical samples, the mother appears to play a more important role than the child in shaping the quality of the infant-mother attachment relationship.The Strange Situation and its associated classification scheme (Ainsworth, Blehar, Waters, & Wall, 1978;Ainsworth & Wittig, 1969) have been the basis of a major body of research on parent-infant relationships. While there are many approaches to the study of parent-infant relationships, the studies relevant for the present paper are those based on the attachment construct äs described by Ainsworth (Ainsworth et al., 1978) and derived from Bowlby's more general concepts of attachment (Bowlby, 1971). A large number of studies of the antecedents and sequelae of attachment classified on the basis of behavior in the Strange Situation (see Bretherton, 1985, for a review) lend credibility to this procedure äs a standardized validated paradigm for assessing infant-mother attachment in this conceptual framework.This study was supported in part by a PIONEER grant from the Netherlands Organization for Scientific Research (NWO) to Marinus H. van IJzendoorn, who is grateful to David G. P. van IJzendoorn for his (non-)verbal comments on earlier drafts of this paper. The idea of a metaanalysis on clinical samples originated with Oded Frenkel and Susan Goldberg. The contributions of Susan Goldberg and Marinus van IJzendoorn are equal. We are grateful to the anonymous reviewers for their comments on an earlier draft of this paper. Requests for reprints should be sent to Marinus H. van