[The mysterious Soviet producer].

The article, using published materials on the history of the Soviet scientific technical intelligence and declassified documents of the Russian archives and the CIA archive, considers issue of the producer applied to start the production of penicillin in the USSR. Currently, dosage of published information, limitation of archival data and specificity of foreign sources makes it impossible to clarify this issue once and for all. However, the article presents number of arguments indirectly indicating likelihood of launching into production penicillin strain procured in the USA by intelligence agent S. M. Semenov.