Regulation of the production of clavine alkaloids, especially elymoclavine, by sucrose, maltose, and mixtures of these saccharides was studied in submerged cultures of strains Claviceps purpurea 129/35 and Claviceps sp. SD-58. The data were statistically processed on an EC 1040 computer. Fermentation medium containing sucrose (80 g/l) in combination with glucose (20 g/l) was the best for elymoclavine formation. Retarded release of glucose from maltose increased the formation of elymoclavine and suppressed the synthesis of undesirable extracellular glucans. Carbon source can affect both the total amount of produced alkaloids and the relative proportion of individual clavines in the alkaloid mixture.