A diagnosis of 22q.11 deletion syndrome (del22q.11) in a child brings with it a plethora of uncertainty in terms of developmental and neuropsychiatric prognosis. This relatively common genetic disorder has a highly variable phenotype with a multitude of potential physical features including palatal anomalies, congenital heart defects, facial dysmorphism, immunodeficiency, and hypoparathyroidism. As a result, patients may present in paediatric, cleft lip/palate, psychiatric, or antenatal clinics. It is necessary, therefore, that the multidisciplinary team are aware of this diagnosis. The overall clinical phenotype ranges from subtle isolated findings to severe multisystem involvement, even in the same family. The neurobehavioural phenotype is also highly variable. The spectrum of developmental delay, learning difficulties, behavioural problems, speech and language deficits, and psychiatric disorders seen in del22q.11 is well recognized. The implications for parents, medical professionals, educational staff and, indeed, the patients are significant. Thus, better understanding of the cognitive and behavioural problems could lead to the development of effective, targeted interventions and improved management.