Iran Press/Europe: In Moscow, Russian President Vladimir Putin and his Turkish counterpart Recep Tayyip Erdogan also agreed to establish a security corridor and joint patrols.
Last month, 36 Turkish soldiers were killed in Idlib during a Russian-backed Syrian government offensive.
Turkey, which backs opposition rebels, responded by attacking Syrian troops.
The agreement was announced after about six hours of talks between Putin and Erdogan in the Russian capital.
The two sides said the deal included:
A ceasefire from 00:01 local time on Friday (22:01 GMT Thursday) on the whole line of contact.
A security corridor 6km (four miles) north and 6km south from Idlib's key M4 motorway, which connects the government-held cities of Aleppo and Latakia.
Joint Russian-Turkish patrols along the M4 from 15 March.
Despite the agreed ceasefire, Turkey "reserves the right to retaliate with all its strength against any attack" by forces of Syrian President Bashar al-Assad, Erdogan warned.
President Putin said he hoped the deal "will serve as a good foundation for ending the fighting in the Idlib de-escalation zone and end the suffering of the civilian population".
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