The meeting took place after recent public statements by the two leaders criticizing each other.
Prime Minister Gordon Brown met with President Hamid Karzai at an air base in Kandahar a day after landing in southern Afghanistan, where more than 9,000 British troops are stationed.
The two leaders, in a show of unity, jointly surveyed a parade of Afghan and NATO troops at the base. Speaking to reporters afterwards, President Karzai insisted his ties with the British Prime Minister remain warm.
"I find him an extremely dignified person and I am happy and honored indeed to call him a friend," Mr. Karzai said. "He has a relationship with me that I can call very trustworthy."
In one of his recent statements, Prime Minister Brown had sharply criticized the Afghan president for not reducing corruption in government offices and for not stepping up training as well as deployment of Afghan security forces. But in a recent interview Mr. Karzai lashed back, saying the British leader's comments were "unfortunate and very artificial and extremely insulting".
But speaking in Kandahar, Mr. Brown also refrained from confrontation and expressed hope the two governments will work together to improve security in Afghanistan and fight corruption in the country.
Mr. Karzai reiterated that his government is determined to improve governance and fight corruption. He said a conference of government officials and civil society representatives is scheduled for Tuesday to discuss as well as devise a strategy to fight corruption.
Earlier, Prime Minister Brown visited British troops and addressed military officers at the Kandahar base. He described troop morale as "exceptionally high", but said the next few months would be critical.
"And I think what we need to show is that there is support from the public at home in Britain, as I know there is, for the work of our forces, that there is a determination to take on the Taliban and to weaken them, but also ... I believe, a determination on the part of the Afghan government to play a bigger part in the future in what is to be done," Mr. Brown said.
In the wake of rising troop casualties, British public support for the presence of their troops in Afghanistan has declined. NATO says 100 British soldiers have died in the country this year.
British Prime Minister Gordon Brown has concluded a previously unannounced trip to Afghanistan, where he visited troops in the troubled south and held talks with President Hamid Karzai on efforts aimed at defeating the Taliban insurgency and improving governance in the country.