The aim of this study was to systematically review literature reporting on the use of external distraction osteogenesis (DO) and internal DO in the treatment of severe maxillary hypoplasia in cleft and palate patients. Literature research has been performed using the PubMed database of the National Library of Medicine and National Institutes of Health from 1966 to August 2007. We used cleft lip and palate and distraction osteogenesis as key words. Of the 104 articles found, we only considered the Anglo-Saxon literature, which reported on the correction of the maxillary hypoplasia with DO techniques. A total of 32 studies reported on anteroposterior external DO (27 studies on rigid external device and 5 on face mask), 17 studies reported on anteroposterior internal DO, and 3 studies reported on transverse internal DO have been retained for this review. Despite the heterogeneity and methodological limitations of most of the studies, results showed that external DO with rigid external device and internal DO resulted to be a more reliable and accurate technique than the face mask in the management of severe maxillary hypoplasia in patients with cleft lip and palate. The current review demonstrated that external and internal DO in the treatment of severe maxillary hypoplasia in cleft and palate patients (1) is a reproducible and valuable alternative to standard orthognathic surgery procedures, (2) allows for a global improvement in facial aesthetic, (3) allows a maxillary correction in patients during the period of mixed dentition, and (4) allows either for an unchanged or better velopharyngeal function.