The diagnosis of psychosocial deprivation dwarfism is difficult. It is also of practical importance since it leads to the only one appropriate treatment: the decision to send the child in a new environment, foster institution or foster family. The present work reports the clinical, biological and psychologic characteristics of 34 children and adolescents aged 9 months to 17 years, in whom a severe growth deficiency had been considered as probably related to psychosocial deprivation, and who were thus sent in foster institutions with good medical and psychological support. The result was in 24 cases a sharp increase of growth rate, giving confirmation of the diagnosis suspected, and in 10 a failure, making this diagnosis unlikely. A comparison of these two groups does not demonstrate any significantly different criterion. The conclusion suggested is thus the following: a trial of at least three months in a foster home, decided on concordant clinical and psychological data, without regard to the biological data, is the only way for distinguishing the truly and falsely deprivation-related dwarfism, or at least to give appropriate support for long-term therapeutic decisions.