A new species of the genus Neisseria is proposed, Neisseria iguanae sp. nov. The organism is associated with septic lesions in the common iguana (Iguana iguana) and the rhinoceros iguana (Cyclura cornuta) but is also a commensal. It resembles N. animalis and N. canis phenotypically but is distinguished from these by exhibiting pronounced tetrad arrangement and alpha haemolysis and by fermenting gluconate.