Nearly 38 percent of couples who have been married for five years or less had no children as of November last year, according to government data.
Among 11.03 million married couples, 37.5 percent were childless, up 1.2 percentage points from the previous year, Statistics Korea said.
Among dual-income couples, 43.3 percent had no children, while the figure was 32 percent for single-income couples.
Of couples where the wives were economically active, 43.7 percent had no children, while the figure was 31.1 percent for couples where the wives were economically inactive.
The percentage of couples without children was higher among those who did not own their homes (41.0 percent) compared with homeowners (33.0 percent).
Among 858,000 recently married couples who had children under the age of 5, almost half -- 47.7 percent -- did not use any child care facilities. Another 46.0 percent sent their children to nursery school and 3.1 percent sent them to kindergarten.
Korea has been struggling with low birthrates. The total fertility rate -- the average number of children a woman bears in her lifetime -- dropped to 1.05 in 2017.
By Yoon Yeun-jung (firstname.lastname@example.org)