A mildly retarded male with a unique interstitial deletion 11 (pter-->q22.3::q23.2-->qter) is described. To the best of our knowledge this patient is the first case with this specific type of deletion. The clinical features and cytogenetic findings of this patient are compared with those of previously reported cases with interstitial deletions 11q and patients with terminal deletions involving band 11q24.1 (leading to the so-called Jacobsen syndrome).