Iran's authorities have banned imported films promoting secularism, feminism, unethical behaviour, drug abuse, violence or alcoholism, reports say.
Mr Ahmadinejad may be trying to show his conservative credentials
Iranian news agencies say the ban was approved by the main decision-making body on cultural affairs, the Supreme Council of Islamic Cultural Revolution.
The council is headed by the Iranian President, Mahmoud Ahmadinejad.
High-ranking officials of Iranian TV and the culture ministry will be charged with implementing the policies.
Much may depend on how strictly this ban is interpreted and enforced.
Some say it may be an attempt by the new president - who comes from a hardline background - to demonstrate to his conservative supporters that he is upholding the values of Iran's Islamic Revolution by cracking down on corrupt Western values.
Foreign films, particularly action and detective films, are shown on Iranian television and cinema, although they are already strictly censored for sexual content, alcohol usage and women wearing revealing clothing.
The new ban could mean that state television, cinemas and arts festivals cut back on the number of foreign films they show.
That would not prevent such films being seen.
Iran has a thriving black market in foreign DVDs. And many Iranians watch satellite TV, despite the fact it is officially banned.
Because the new ban does not apply to Iranian-made films, Iran's thriving film industry should theoretically be unaffected.
But some analysts say it could cause nervousness and might tempt some Iranian directors to apply self-censorship for fear of closer scrutiny by the authorities.
One film director told the BBC that he feared the vagueness of some of the terms included in the new ban could give a free hand to judges in Iran's conservative judiciary to interpret it as they wished.