The ceasefire was set to expire at the end of December.
Sudan has extended a unilateral ceasefire with rebels until the end of March, state news agency SUNA reported on Thursday, citing a presidential decree.
In October, the United States lifted 20-year-old sanctions tied to progress on progress on counter terrorism cooperation and on resolving internal conflicts.
Fighting between the army and rebels in the Kordofan and Blue Nile regions broke out in 2011, when South Sudan declared independence. Conflict in Darfur began in 2003 when mainly non-Arab tribes took up arms against Sudan’s Arab-led government.
The ceasefire was set to expire at the end of December.