A basic assumption in psychotherapy with children is that the parent-child relationship is central to the child's development. This article describes the Joint Painting Procedure, an art-based assessment for evaluating relationships with respect to the two main developmental tasks of middle childhood: (a) the parent's ability to monitor and supervise the child while experiencing the child's newly developing capacity for self-management, and (b) the ability of the parent and child to maintain a positive and close relationship with each other. Case examples illustrate the Joint Painting Procedure in art therapy and three of the scales used to evaluate the results. Joint painting enables multidimensional expression and representation of implicit characteristics of a relationship that cannot be expressed verbally. (Contains 2 tables and 3 figures.)