The paper deals with one hundred and ninety nine species of diverse invertebrate groups of interstitial fauna collected during a survey of the Andaman and Nicobar group of Islands undertaken by the Zoological Survey of India in February-April, 1969. All these species have been recorded for the first time from the Islands. The occurrence of the fauna in relation to relative abundance, localities from where they have been recorded, the level of intertidal zone, nature of the substrate, etc., are given. The percentage composition and the distribution of the fauna in relation to the physiography of the islands have also been discussed.