A new colony of Cormorants was found on the artificial island ’De Hond’ in the Dutch Wadden Sea (53°23,9 N, 6°55,2 E) during a visit on 10 September 1992. The visit was made to collect pellets of Cormorants which were only known to roost on the island. Some 30 disintegrated nests were found as well as 4 dead hatchlings. We were informed that breeding on the island had in fact been taking place for at least 15 years and that some 50-60 Cormorants had bred in 1992. This is the first known truely marine colony of this species in the Netherlands. The colony is well protected. The island, in use by the Dutch Gas Company (NAM), is only seldom visited. Barbed wire was replaced by wire that was less harmful for the birds and a roof was placed over the gas-installation in order to separate breeding birds and installation, without preventing the Cormorants to build nests.