According to the office of the president, Niinistö and Trump discussed the state of international relations in general. The office said the discussion was held on Finland's initiative.
The two heads of state also discussed issues concerning the Arctic region, the office said, noting that Finland is currently chair of the Arctic Council.
Niinistö also told Trump he hopes that the US President's meetings this week with French President Emmanuel Macron and German Chancellor Angela Merkel are fruitful.
This week Macron began a three-day visit to Washington and will meet with Trump while Merkel is due to meet the US president on Friday. Macron and Trump are expected to discuss the Iran nuclear deal and trade relations, while Merkel is also said to be planning to discuss international trade.
During Niinistö's and Trump's conversation, the US president again congratulated the Finnish president on winning the election for his second term in January, according to the Finnish president's office.