The six-week truce was signed in the city of Abeche in Chad late on Wednesday, reported Omdurman state radio on Thursday.
The agreement was signed by Sudanese General Issmat Abd al-Rahman Zinilabdin, commander of the western region, and Abd Allah al-Bakr representing the Sudan Liberation Movement (SLM).
Earlier this week the SLM said it had agreed in principle to a ceasefire during indirect talks over the weekend in Chad, to end months of sporadic clashes with government troops in Darfur.
The talks in Abeche, 300km from the Sudanese border, were conducted through mediation by Chadian President, Idriss Diby, and other officials.
The parties also agreed to control armed irregular groups and made a commitment to consolidate peace and stability in order to push forward development and prosperity in the area, reported Radio Omdurman.
The two sides agreed to form a “tripartite committee comprising representatives from the Sudanese government, SLM and the Chadian government to follow up on the implementation of the agreement”.
They planned to make arrangements for negotiations at the final stage of talks.
The SLM was known as the Darfur Liberation Movement in August 2001 before re-emerging under its current name last February, when it began claiming responsibility for a series of anti-government attacks.