"An unprecedented delegation filled with optimism for common peace and development with our brothers left for Kabul this morning," army spokesman Major General Asim Saleem Bajwa said.
Foreign Office said that Sharif was invited by President Ashraf Ghani and is accompanied by Sartaj Aziz, Advisor to the Prime Minister on National Security and Foreign Affairs; Gen. Raheel Shairf, Chief of Army Staff; Syed Tariq Fatemi, Special Assistant to the Prime Minister on Foreign Affairs; Foreign Secretary Aizaz Ahmad Chaudhry and senior officials.
Other engagements of the Prime Minister will include a meeting with the Afghan Chief Executive, Abdullah Abdullah and delegation-level talks with the Afghan side.
Sources said that the issue of peace talks with Taliban will be prominent in the talks as Afghan government wants to end the conflict through settlement with the militants.
Pakistan on its side will ask Kabul to take action against rebel chief Mullah Fazlullah, who is allegedly hiding in the country and overseeing militant activities in Pakistan.
According to Pakistani media reports, the delegation may also raise the issue of RAW's alleged activities in Pakistan as last week military chief expressed concern over Indian spy agency's alleged support for militants in Pakistan.
Security officials allege that India is using Afghan soil to destabilise Pakistan's Balochistan province.
Both Kabul and New Delhi deny this.
The Foreign Office said building close cooperative relations with Afghanistan is a high priority in Pakistan's foreign policy and a vital component of Prime Minister Sharif's vision of a "peaceful neighbourhood".
His visit is taking place at a time when bilateral relations between the two countries are underpinned by unprecedented warmth, mutual trust and a shared vision of working in lockstep to build a peaceful and stable region.
His visit to Afghanistan would further strengthen the positive momentum in bilateral relations and help intensify common endeavours in the pursuit of durable peace, stability and prosperity in the region.
This will be Sharif's second visit to Afghanistan and the first after the installation of a national unity government in Kabul. Earlier, he visited Afghanistan on November 30, 2013.
After months of secret efforts, the Taliban and Afghan officials had face-to-face interaction in Qatar last week.