OBJECTIVES: The aims of this study were to investigate and describe oral manifestations in 22q11 deletion syndrome, and to relate the findings to medical conditions. DESIGN: Cross-sectional. SAMPLE AND METHODS: Fifty-three consecutive patients from Sweden referred to the Sahlgrenska University Hospital during a 3-year period were included, median age 8 yrs (range 2-43; mean age 11.09). All but six patients were children 3-19-years-old. The patients were examined concerning oral mucosa, dental anomalies, dental caries, occlusal development, and eruption of the teeth. The clinical findings were compared to medical data and case history. RESULTS: Dental anomalies were registered in high numbers. Enamel hypoplasia was found in 16 patients. In 13 cases this was documented in primary teeth, of which 10 patients had symmetrical and chronological defects. Enamel hypomineralization was found in 23 patients and was equally common in both primary and permanent teeth. The use of computerized inductive analyses revealed that enamel hypoplasia was associated with medical conditions like preterm birth and congenital heart malformation while hypomineralization was associated with more diffuse conditions like frequent infections. Hypodontia was registered in seven patients, while eight had aberrant tooth shape, and nine patients presented delayed tooth eruption. The patients had an average of 4.6 carious or filled teeth and the oral health was assessed as impaired in 15 patients who had severe dental caries (5-18 carious teeth or multiple active incipient caries lesions). CONCLUSIONS: In 22q11 deletion syndrome the oral cavity is affected by anomalies in dental enamel, tooth shape, numbers of teeth, and eruption. Dental health problems due to caries are common. This is of special importance as patients with 22q11 deletion syndrome frequently present with congenital heart malformations and immunological problems.