Children's attachment patterns at early preschool age and 2 years later as well as factors related to stability-instability were examined in a diverse socioeconomic status French Canadian sample of 120 children. Attachment was assessed during 2 laboratory visits using separation-reunion procedures when the children were approximately 3.5 (J. Cassidy & R. S. Marvin, 1992) and 5.5 (M. Main & J. Cassidy, 1988) years old. Overall, stability of attachment, based on 4-way classification, was moderate (68 percent, k = 0.47, p = 0.01). Change from security to disorganization was associated with the most dramatic decline in interactive quality with mother, lowest marital satisfaction, and greatest likelihood of severe attachment-related family events, namely, loss and parental hospitalization. Families of children who changed from security to organized insecurity presented levels of caregiving and marital dissatisfaction that fell between those of stable secure children and secure children who changed toward disorganization.