Avito had been one of Prosus's most valuable investments until Russia's invasion of Ukraine on Feb. 24, which Moscow describes as a "special military operation", with an estimated valuation of about $6 billion.
"Prosus has now decided to exit the Russian business," the company said in a statement. "We have started the search for an appropriate buyer for our shares in Avito."
Separately, Moscow-headquartered Avito said it would continue to operate as a standalone business, run by Russian management.
"This does not affect Avito's business development plans and opportunities in Russia," the company said in a statement.
In March, Prosus said it would cut ties with Avito and would not seek to benefit economically from its ownership.
As sanctions were imposed on Russia after its invasion of Ukraine, Prosus initially decided to continue running Avito, noting that it had responsibility for the company's 4,000 employees.
That decision was criticised after it emerged that Avito had carried advertisements for Russian military jobs.
Prosus then said it would separate Avito from its online marketplace businesses, part of the larger OLX Group, but had not clarified what would happen after the separation.
Prosus is controlled by Naspers of South Africa. Its shares have fallen by more than 40% over the past year, largely tracking the value of its biggest asset, a 28.9% stake in Chinese online media giant Tencent.
Prosus shares traded 2.4% higher at 46.61 at 0715 GMT in Amsterdam on Friday.
(Reporting by Toby Sterling; editing by Jason Neely, Robert Birsel)