The South Korean company said in a statement it found evidence of an "illegal hiring process" after conducting an investigation of a supplier in southeast China's Guangdong province, Dongguan Shinyang Electronics.
Dongguan Shinyang is a subsidiary of a South Korean firm, Shinyang Engineering Co.
The announcement came a week after a New York-based human rights group, China Labor Watch, claimed "at least five child workers" were employed at the supplier.
The statement by Samsung said, "As part of its pledge against child labor, Samsung routinely conducts inspections to monitor its suppliers in China to ensure they follow the commitment, and has provided necessary support."
Samsung threatened to permanently sever its relationship to the supplier if an investigation by Chinese authorities proves the rights group's claims are true.