The development is a major milestone in Iran's atomic programme despite UN sanctions.
The transfer took place under the scrutiny of International Atomic Energy Agency [IAEA] inspectors, according to a statement by Iran's atomic energy organisation.
"The operation of transferring nuclear fuel to the reactor was carried out in [the] presence of Ali Akbar Salehi, vice-president and head of Iran's atomic body, and Sergei Kiriyenko, head of Russia's atomic body, Rosatom," it said.
Al Jazeera's Neave Barker, reporting from Moscow, said it will take "several months before the plant is up and running fully and, according to Rosatom, Russia will continue to play an active role in the running of the plant for several more years."Fuel 'pool'A first lorry-load of fuel was taken from a storage site to a fuel "pool" inside the reactor building on Saturday.
Over the next 10 days, 163 fuel rods - equal to 80 tonnes of uranium fuel - will be moved inside the building and then into the reactor core "after necessary inspections", the statement said.