Child psychiatric nursing evolved gradually as the therapeutic value of nurses relationship with children began to be realized. Common childhood and adolescent psychiatric disorders discussed are mental retardation, childhood autism, hyperkinetic disorder, conduct disorders and separation anxiety disorder. This chapter focuses on etiology of disorders of childhood and adolescents, which usually occur as a result of complex reactions during once early developmental stages. The clinical symptoms and diagnostic characteristics are also presented. Nursing care for children and adolescents is discussed using the nursing process approach.