The sizes of dental arches in 129 children with cleft palate were evaluated retrospectively from dental casts taken at the mean age 6.2 years (range 5.2-7.5). The material included 61 children with submucous cleft palate (SMCP) and 68 children with isolated cleft palate (ICP). Twenty of the children with SMCP were not operated on, while 41 had had surgical treatment, either palatal repair (n = 16, mean age at operation: 1.6 years, range 0.8-3.9) or pharyngeal flap (VPP) surgery (n = 25, mean age at operation: 4.5 years, range 2.6-6.2). In children with ICP, one-stage hard-palate and soft-palate closure had been done at the mean age of 1.5 years (range 1.0-2.1). Decreased maxillary intermolar widths were seen in children with SMCP after VPP, and especially after palatal repair. The children with ICP had the smallest maxillary dental arch widths. No significant differences were observed in the maxillary arch length or mandibular intermolar arch dimensions in children with SMCP or ICP. Surgery is associated with decreased maxillary intermolar arch widths in children with SMCP. Children with ICP had smaller maxillary dental arch widths than children SMCP.