Summary In a comparative study of various types of anal swabs and scrapers now in use or devised by us for the diagnosis of oxyuriasis, a new type of swab, consisting of a glass rod inserted in a perforated cork and with the tip of the rod covered with a small square of cellophane, the assembled set-up completed by inserting the cellophane-tipped end of the rod in a small test tube which is corked with the perforated cork, has been found to be the most satisfactory form of swab and superior to the scrapers tested. This swab, used as indicated in the paper, conforms to the specifications for a satisfactory swab as outlined in the paper. It is designated as the NIH swab. It acts both as a swab and a scraper.