Recent developments in microarray technology have revealed the presence of many submicroscopic deletions and duplications in the human genome. Some of these have been found to increase the risk for neuropsychiatric disorders. Over the last 2 years, several large studies on schizophrenia have implicated large deletions and duplications that increase the risk of developing this disorder. It is now clear that rare deletions at 1q21.1, 15q13.3, 15q11.2 and 22q11.2, as well as duplications at 16p11.2 and 16p13.1, increase the risk of developing schizophrenia. They are found collectively in up to 3% of patients; therefore, they account for only a small proportion of the genetic causes of schizophrenia. In this paper I will review the evidence for these findings.