"My tenure ends on 29th November 2013. On that day I will retire. May the Almighty Allah help and guide us all," Kayani said in a statement.
Kayani was appointed the army chief by former military ruler Pervez Musharraf in late 2007. He was given an unprecedented three-year extension by then premier Yousuf Raza Gilani in 2010.
In a surprise announcement, he said institutions and traditions are stronger than individuals and must take precedence. He also reposed military's support to democracy.
61-year-old Kayani said he was grateful to the political leadership and the nation for reposing their trust in him and Pakistan Army at this important juncture of country's national history.
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"However, I share the general opinion that institutions and traditions are stronger than individuals and must take precedence," he said.
Kayani underlined that as he completes his tenure, the will of the people has taken root and a constitutional order is in place.
"They have also proven, on countless occasions, through their priceless sacrifices that the defence and prosperity of Pakistan is their highest priority," he said.