The children of migrant workers are often targets
China has executed two men convicted of abducting and selling children, state media has reported.
Hu Minghua, 55, and Su Binde, 27 were earlier found guilty of kidnapping and selling 15 children, mostly young boys, Xinhua news agency said.
It said only six of the children, most of them aged between three and six, had been returned to their families.
Last month Chinese police said they had recovered more than 2,000 children in a six-month campaign against trafficking.
In the latest case, it is unclear whom the children were being sold to.
But the BBC's Damien Grammaticas in Beijing says China's "one-child" policy - combined with a preference for sons - is party responsible for the rise in child trafficking within the country.
Some parents are prepared to buy a stolen child if they can not have a boy of their own, our correspondent says.
Boys in China can be bought for about $5,000 (£3,036) each. They are prized as they continue the family name and traditionally care for elderly parents, our correspondent adds.
Hu Minghua and Su Binde were executed on Thursday, Xinhua said.
Hu had been convicted of snatching and selling nine children in 1999-2005, while Su had been found guilty for kidnapping and selling six children in 2005-06.
Many of the children are snatched while playing on the street or waiting at bus and train stations.
Their parents are often poor migrant workers unable to keep a constant watch over the children.
In its attempt to try to curb the trade, China has this year handed down a total of 1,700 convictions.
Since April, 2,008 children have been rescued across the country, and some have already been reunited with their parents, officials say.