Trump suggested that the US could accept Russia's annexation of Crimea if it led to improved relations between the two nations
"Not one state in the world, except it seems to me North Korea and Venezuela, recognises Crimea," Poroshenko told a joint news conference with Swedish Prime Minister Stefan Lofven in Stockholm.
The "United States is not North Korea. And let's respect United States' people, the United States and the United States president," he added.
When asked about the possibility of "an agreement" with Trump and Russian President Vladimir Putin about recognising Crimea, Poroshenko responded: "I am absolutely sure that the new president-elect is completely strong enough in an effective cooperation with Ukraine ... no doubt."
In an interview with ABC in August, Trump suggested that the US could accept Russia's annexation of Crimea if it led to improved relations between the two nations, which are bitterly at odds over Syria.
Trump, who takes over as US president in January, criticised President Barack Obama's foreign policy stance during the election campaign saying it had caused a sharp deterioration in relations with Russia.
US-Russia relations dipped to their worst since the Cold War after Moscow's annexation of Ukraine's Crimea peninsula in March 2014, and Russia also has been accused by Washington of supporting pro-Russian rebels in eastern Ukraine.
Poroshenko called for the extension of Western sanctions against Russia.
"We need European unity. Unity in the European Union, and transatlantic unity," he said.