Radev has to dissolve the parliament after the Socialists became the third political party to refuse to form a regular government in a deadlocked parliament.
Bulgaria, European Union's poorest and one of its most corrupt member states, has been rocked by political instability since anti-graft protests in 2020.
It has been governed by caretaker governments, appointed by Radev for much of the past two years in the absence of a stable elected coalition.
Radev said he would dissolve the parliament on Feb.3, and expressed hope lawmakers would use the time until then to approve legislation - mainly linked to combating high-level graft - to ensure the country's access to hefty EU aid.
"I will issue a decree to dissolve the National Assembly on Feb. 3 and will appoint the parliamentary election on April 2," Radev told reporters.
"I hope that lawmakers will use the time to prove that fight against corruption... and the European integration are a genuine priority and not just an election pledge," he said.
Radev has said earlier he would re-appoint current interim prime minister Galab Donev to lead the country until a new government is formed after the snap polls.
The prolonged political turmoil is weighing on Bulgaria's plans to join the euro zone in 2024. The political crisis is likely to delay much needed reforms to combat high-level graft and hamper Bulgaria's ability to use efficiently EU funds.
(Reporting by Tsvetelia Tsolova; Editing by Frank Jack Daniel and Angus MacSwan)
