The Cardassian Ambassador to the United Federation of Planets was the permanent diplomatic representative of the Cardassian Union to the Federation. The position held particular clout amongst the lesser powers because of the intermediate level of power wielded by the Cardassian Union prior to the Dominion War.
In 2378, the Cardassian Ambassador to the United Federation of Planets was Elim Garak. He continued to serve in this position until September, 2385, where he was elected to the office of Castellan of the Cardassian Union, succeeding Rakena Garan. Occurring shortly after the assassination of Federation President Nanietta Bacco. (DS9 novel: The Never-Ending Sacrifice; ST - The Fall novel: The Crimson Shadow)