A few demonstrators were injured in stone-throwing incidents protesting against corrupt officials and rising crime, including child kidnapping, witness said on Monday.
"We want the governor to take immediate and serious action against crime here," said one protester. "There is too much bribery, and we face a threat from child kidnappers."
Governor Gul Agha Sherzai, a former mujahidin commander and federal minister, was dropped from President Hamid Karzai's cabinet in December. But the president gave Sherzai back his old post of southern province governor.
Kandahar is rife with banditry and tribal rivalries, while remnants of the Taliban are still active, running a guerrilla campaign against US-led forces and the new Afghan army.
There have been many reports of child kidnapping in Afghanistan, and people suspect the children are taken overseas and either forced into the sex trade, used by drug runners, or used as captive donors for a black market in human organs.