Saberi was jailed last month for eight years on charges of spying for the US, but following international outcry her sentence was reduced to two years, suspended for five years. She is now free to leave Iran.
"We are delighted that justice has been served by the appeal process and that Roxana Saberi is due to be released from prison in Tehran today," said Hassiba Hadj Sahraoui, Amnesty International's deputy director for the Middle East and north Africa.
"She should, however, never have been imprisoned in the first place."
Sahraoui added the release must be "unconditional" and said Amnesty was "concerned that she may face travel restrictions".
Amnesty also urged Iran to release all other "prisoners of conscience".
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