Eating disorders not otherwise specified are the most common category of eating disorders encountered in routine clinical practice. Their prevalence fluctuates from 2.4% to 12.6% among female adolescents and up to 60% of cases in treatment centres. Binge eating disorder is the most differentiated subtype. Peripuberal period, diabetes mellitus type I, intense and increased physical activity, demographic and psychosociocultural aspects, physical and psychopathological diseases are risk factors. Clinical features, course, outcome and therapeutic approaches are similar to those of full syndromes. From an etiological point of view, some authors believe that there is a continuum from altered eating behaviors and concerns about body shape and weight to typical anorectic and/or bulimic disorders. Others classify them as subcategories of full or mixed disorders. In conclusion, these conditions are heterogeneous syndromes that need to be reconsidered from both nosological and conceptual perspectives. They also demand an early recognition and treatment and further research about these disorders is required.