Ergot alkaloids are very important pharmaceutical substances with wide medical use. Their bioproduction is usually followed by chemical modification. Bioconversions of ergot alkaloids on an industrial scale have become more important in recent years. The aim of this study is to collect the available data on ergot alkaloid bioconversions and to show their potential applications. The paper deals with conversions of clavines, e.g. biooxidations, glycosylations of the alkaloids, and bioconversions of lysergic acid derivatives. A part of it is aimed at bioconversions of ergot alkaloids in mammalian organisms and obtaining their metabolites by biotransformation. The use of immobilized systems and cofermentation is also discussed.