This paper presents the problematic features of making decisions related to the assessment and treatment of children, highlighting the importance of the diagnostic procedure in determining the need and type of therapy. Difficulties in assessing children are discussed in terms of the reliability of assessors, evaluation techniques, information sources, and children's functioning in different settings. Unique, complicating childhood characteristics are depicted: most disorders' normative basis in children's development; rapid, continuous change; gaps between cognitive, affective, behavioral, and chronological developmental stages; and high spontaneous recovery rates. Within an emphasis on the therapist's need for self-awareness and flexibility of child assessment and treatment methods, decision-making guidelines to evaluate the need for therapy are suggested and case examples are provided.