Russia’s invasion, and its blockade of Ukraine’s grain exports, have sparked grain and fertiliser shortages and put millions of people at risk of hunger.
The chair of the AU commission said there was an “urgent need for dialogue” to restore global stability.
Western countries have urged Russia to release Ukraine’s vast grain stores.
The blockade has sent food prices soaring.
“Africa is actually a hostageā¦ of those who unleashed war against our state”, Mr Zelensky said in his speech.
He said his government was engaged in “complex negotiations” to unblock grain reserves trapped in Ukraine’s Black Sea ports.
“This war may seem very distant to you and your countries,” he told the AU. “But the food prices that are catastrophically rising have already brought [the war] to the homes of millions of African families.”
Mr Zelensky’s AU speech comes nearly 10 weeks after he first asked to address the continental body.
The BBC understands that 55 heads of state were invited to the virtual session, but only four attended. The rest of the countries sent representatives.
African countries have been divided in their response to Russia’s war in Ukraine. In March, 17 African countries abstained in a UN vote to condemn the invasion.
But on Monday, AU’s chairperson Macky Sall thanked Mr Zelensky for addressing the union.
Mr Sall said that “Africa remains committed to respecting the rules of international law, the peaceful resolution of conflicts and freedom of trade”.
Initially, the AU did not want to be addressed by Mr Zelensky, and it does not fully agree with what he’s saying – they want dialogue to solve the crisis, as they always have.
Earlier this month, Mr Sall held talks with Russia President Vladimir Putin. He told Mr Putin that African countries are innocent victims of the war in Ukraine and Russia should help ease their suffering.
Earlier on Monday, EU foreign policy chief Josep Borrell said of Russia’s blockade: “This is a real war crime, so I cannot imagine that this will last much longer.”
Mr Borrell met EU foreign ministers in Luxembourg on Monday to discuss the crisis.
He described Moscow’s actions as “a deliberate attempt to create hunger in the world”.
He rejected Russia’s claim that the current food crisis is a result of EU sanctions, adding that they “don’t forbid” countries outside the EU from conducting food trade with Russia or other nations.