To compare craniofacial structure and growth, two standard lateral cephalograms of 35 children with Pierre Robin syndrome and 30 age and sex matched children with isolated cleft palate were taken at two different ages. The mean (SD) age of the children with Pierre Robin syndrome was 9.5 (3.0) years and of the children with isolated cleft palate 7.1 (1.1) years at the start of the follow up period. The follow up time in the first group was 4.3 (1.6) and in the second group 3.8 (2.7) years. There were no significant differences between the groups in the shape of the cranial base or the maxilla. The main differences were in the mandible, which showed more recession among those with Pierre Robin syndrome. There was a significant correlation between the shape of the maxilla and that of the mandible in that group, but not in the group with isolated cleft palate. During the follow up period there were no significant differences between the two groups in the rate of growth of the jaws. The association between the maxilla and the mandible (ss-n-sm) remained unchanged, or increased, or decreased with equal frequency in both groups. There was no catch up mandibular growth among the children with Pierre Robin syndrome.