Gazprom will help Iran's national oil company in the development of gas and oil fields, as well as the completion of liquefied natural gas projects and construction of gas export pipelines.
The National Iranian Oil Company (NIOC) and Russian gas producer Gazprom have signed a memorandum of understanding worth around $40 billion.
The deal was signed during an online ceremony by the CEOs of both companies on Tuesday, Iran's oil ministry's news agency SHANA reported.
Gazprom will help NIOC in the development of the Kish and North Pars gas fields and also six oil fields, according to SHANA.
The company will also be involved in the completion of liquefied natural gas (LNG) projects and construction of gas export pipelines.
The memorandum comes on the day Russian President Vladimir Putin arrives in Tehran for a summit with his Iranian and Turkish counterparts.
Iran sits on the world’s second-largest gas reserves after Russia, but US sanctions have hindered access to technology and slowed development of gas exports.
Putin's visit to Tehran is being watched closely as Russia's offensive in Ukraine has reconfigured the global oil and gas market, pushing prices to high levels which contribute to higher living costs and rising consumer inflation.