Taha and the head of the Sudan People's Liberation Movement/Army (SPLM/A) signed the Nairobi Declaration on the Final Phase on Peace in Sudan on Saturday at a ceremony hosted by Kenyan President Mwai Kibaki in Nairobi.
The document incorporates six accords struck over the course of two years of talks on issues such as power, wealth-sharing and the establishment of a six-year interim period of autonomy for south Sudan.
The final round of talks covers a comprehensive ceasefire and technical aspects of its implementation. Actual negotiations are due to resume on 22 June.
Before a gathering of foreign dignitaries, including Arab League Secretary General Amr Musa and Egyptian Foreign Minister Ahmad Mahr, Taha and Garang held aloft copies of the document in which both sides pledged to wrap up negotiations as soon as possible.
The peace talks do not cover a separate conflict in Sudan's western region of Darfur, which the United Nations says has created the world's worst humanitarian crisis.
Mediators in Kenya, where talks are being held, have said a final deal could be concluded within two months.
The government and the SPLM/A rebels signed landmark protocols on 26 May on how to share power and manage three disputed areas.
Previous accords relate to a vote in the south on secession after a six-year transition period, forming a post-war national army and the equal division of oil revenues during the interim.
Sudan's civil war has killed an estimated two million people, mainly through famine and disease since 1983 when Khartoum tried to impose Islamic Sharia law on the mainly animist south.
Oil, religion and ideology have been complicating factors in the war.