It named her as a vice director alongside the head of the Propaganda and Agitation Department, which handles ideological messaging through the media, arts and culture.
Kim Yo Jong's title supports earlier reports from a North Korean defector group which said she may have taken a high-level role when Kim Jong Un recently disappeared from public view for more than a month, prompting speculation about his grip on power. South Korea's intelligence agency later said Kim, 31, was likely to have had surgery on his left ankle.
Kim has since reappeared, walking with a limp. Kim Yo Jong's power has been likened to that of a prime minister, an unnamed South Korean intelligence source told the Seoul-based JoongAng Ilbo newspaper in April. "All roads lead to Comrade Yo Jong," the source said. Kim Yo Jong has featured in state propaganda since her brother took over the nuclear-capable country upon the death of their father, Kim Jong Il, in late 2011.