The unemployment rate for young people, aged 15 to 29, jumped to 11.1 percent in February from 9.2 percent a month earlier, the Statistics Korea said Wednesday.
It is the highest since 2000 when the agency began to compile corresponding data.
It said the nation's overall jobless rate rose to 4.6 percent last month from 3.8 percent in January on seasonal factors and increased jobseekers.
Seasonally-adjusted, the jobless rate also rose to 3.9 percent from 3.4 percent, the highest since February of 2010.
Despite the rise in the jobless rate, the number of people with jobs increased.
The number of the employed rose to 25.19 million last month from 25.11 million in January.
It said 376,000 new jobs were created in the month, compared with 347,000 in January and 422,000 in December.