This is the first of a series of studies dealing with the psychosomatic aspects of clinical allergy. A sharp distinction is drawn between clinical allergy and allergy in an immunologic sense. Psychologic factors do not produce immunologic allergy but do play an important role, along with infections and mechanical, chemical and radiant trauma, in precipitating and aggravating the symptoms of clinical allergy. The relationship between maternal rejection and allergic reactions is specifically investigated. 63 children having clinical symptoms of hay fever, eczema, or urticaria were included in the study. A control group was composed of 37 nonallergic children referred for psychotherapy. Psychologic data were obtained from both groups by means of a diagnostic session with the child and an interview with one or both parents. The incidence of maternal rejection in the group of nonallergic children was found to be 24.3%, a figure which approximates that previously found among problem children. In the group suffering from symptoms of clinical allergy the difference was striking. Maternal rejection occurred in 62 of the 63 cases studied. The compensative attitude of maternal overprotection was apparent in 57.1% of allergic children but in only 10.8% of the nonallergic group. Further data indicated a close relationship between maternal rejection and sexual maladjustment between the parents. It is concluded that maternal rejection is an important factor in the pattern of clinical allergy.