There are several varieties of English where rhyming slang is or has been a productive source of new words. However, its incidence in some Englishes still remains, by and large,terra incognita for slang lexicographers and linguists alike. Based on a number of written sources and oral transcripts, this article surveys the origins and development of rhyming slang in Ireland, its most outstanding characteristics and its productivity throughout the 20th century down to the present. In order to illustrate the significance and creative potential of this category of word-formation in Irish English, the final part of the article offers a glossary of Irish rhyming slang, including many terms which are not recorded in the standard slang dictionaries.