sources for the replication and transmission of the element and not compromising the fitness of the host cell. An evaluation of the deoxyribonucleic acid (DNA) plasmid species found naturally in yeasts presents an anthology of approaches to stable, extrachromosomal persistence. In this review we describe all the DNA plasmids that have been isolated and characterized from different yeasts, focusing our attention on the mechanisms underlying their successful existence as extrachromosomal elements.