Iraqi Prime Minister Mustafa al-Kadhemi arrived in Tehran on Tuesday in his first visit abroad since taking power, Iranian state television reported.
Kadhemi, who was greeted by officials at Mehrabad airport, is expected to meet President Hassan Rouhani and supreme leader Ayatollah Ali Khamenei, among other senior officials.
His delegation includes Iraq's ministers of foreign affairs, finance, health and planning, as well as his national security adviser, the broadcaster said.
The Iraqi premier had been scheduled to visit Saudi Arabia as his first trip abroad, then quickly follow it up with a trip to Tehran in a carefully calibrated balancing act between the two regional rivals.
However the Saudi leg of his trip was postponed after King Salman was hospitalised on Monday.
Baghdad has often found itself caught in the tug-of-war between Riyadh, Tehran and even Washington, which Kadhemi is also set to visit within the next few weeks.
Kadhemi rose to the premiership in May after serving as the head of Iraq's National Intelligence Service for nearly four years.
He formed close ties to Tehran, Washington and Riyadh during that time, prompting speculation he could serve as a rare mediator among the capitals.
The prime minister's trip to Tehran comes after receiving Iran's top diplomat Mohammad Javad Zarif in Baghdad on Sunday.