Fifteen percent of young Korean adults aged between 15 and 29 are jobless and not searching for work, according to a report by the Organization for Economic Cooperation and Development (OECD), Tuesday.
This the third highest figure among 33 OECD members surveyed.
Such young people are often referred to as NEETs, short for those Not in Education, Employment or Training.
According to the report, Korea's ratio of NEETs was 15.6 percent as of 2013, and only Turkey and Mexico had higher ratios, 24.9 percent and 18.5 percent, respectively.
The OECD average was 8.2 percent.
Korea was followed by Italy, Hungary, the United States and Israel with 14.4 percent, 11.3 percent, 10.8 percent and 10 percent.
Japan's figure was 4.6 percent, and Greece, 6.7 percent. Luxembourg reported the lowest rate with 2.6 percent.
Experts say Korea has such a high ratio partly because of the poor quality of jobs available.
In a separate study by Hyundai Research Institute earlier this year, many NEETs fell into their situation after having part-time jobs with less than a one-year contract.
"The government tends to focus only on increasing the number of jobs instead of their quality or stability. If that stance does not change, the situation will not improve," a researcher at the institute said.
"Such young people will have delayed employment, and thus financial pressure will delay marriage and childbirth, resulting in other social problems."
In a related report by Statistics Korea last month, the number of jobless young people aged between 20 and 29 reached an all-time high at 410,000.
It also showed that many young people had to take poor quality jobs on short-term contracts for minimum wage. More than 34 percent chose part-time jobs as their first form of employment, which ended after an average of 14.6 months.