The authors treated three patients who chiefly complained functional anterior crossbite due to premature loss of primary molars by using removable space maintainer and functional appliances. In orthodontic practice, the mandibular rest position and the possibility of taking construction bite have been as the criteria for evaluation of functional factors involved in anterior crossbite. Functional anterior crossbites, if left untreated, may have deleterious effects on the development and function of craniofacial complex and TMJ. Objectives of the treatment were as follows: 1) to recover vertical dimension 2) to eliminate functional disharmony 3) to correct anterior reversed occlusion 4) to attain good facial esthetics 5) to prevent unfavorable growth of jaw & dentition Characterized craniofacial morphology resulting from the premature loss of deciduous molars could be recovered following the correction of crossbite. Therefore, it is recommended that in orthodontic diagnosis of functional anterior crossbite due to premature loss of deciduous molars, the craniofacial abnormality affected by that should be considered.