De Mistura, a dual citizen of Italy and Sweden, was chosen to replace Lakhdar Brahimi as the international envoy for Syria in July.
On Tuesday afternoon local time, he attended residence of Foreign Minister Zarif in New York to discuss the developments in Syria.
During the meeting, Zarif referred to the terrorist activities of Daesh (ISIS) in Syria noting, "The fight against terrorism which was emphasized by Iran from the early days of its emergence, has now become an international priority."
He welcomed primary moves made by de Mistura in Syria including the exchange of views with both government officials and opposition groups to reach a peaceful solution for the country's political crisis describing it "a step taken in right direction".
Meanwhile, de Mistura, a former UN special envoy to Afghanistan and Iraq, briefed Zarif on separate meetings the former had held with Syrian President Bashar al-Assad and with moderate opponents of his government to reach a peaceful solution for the country's political crisis.
The envoy on Syria added he is to make more visits to regional countries to exchange views on Syria.
While in New York, Foreign Minister Zarif has so far held separate meetings with his counterparts form other countries including Armenia and Bolivia to discuss issues of mutual interests.
The Iranian minister is in New York for the seventh round of nuclear talks with the Group 5+1 which are being held on the sidelines of the 69th session of the UN General Assembly.
The 69th session convened at UN Headquarters on September 16 and its General Debate will open on Wednesday, 24 September.
Based on the schedule, President Hassan Rouhani who arrived in New York on September 22 will address the UNGA Thursday morning as the second speaker.