He studied at the University of Saint Petersburg under Andrei Famintsyn in 1887, when he was sent to Ukraine and Bessarabia to investigate a tobacco disease causing great damage to plantations located there at the time.

Three years later, he was assigned to look into a similar disease occurrence of tobacco plants, this time raging in the Crimea region.

He discovered that both incidents of disease were caused by an extremely minuscule infectious agent, capable of permeating porcelain Pasteur-Chamberland filters, something which bacteria could never do.

In 1898, the Dutch microbiologist Martinus Beijerinck independently replicated Ivanovsky's experiments and became convinced that the filtered solution contained a new form of infectious agent, which he named virus.

Beijerinck subsequently acknowledged Ivanovsky's priority in the discovery of the filterable, submicroscopic entity.