It said the court "sentenced each of them to 12 years of reform through labor." The KCNA report gave no other details.
Ling and Lee - who were working for former Vice President Al Gore's California-based Current TV - cannot appeal because they were tried in North Korea's highest court, where decisions are final.
The circumstances surrounding the trial of the two journalists and their arrest March 17 on the China-North Korean border have been shrouded in secrecy, as is typical of the reclusive nation. The trial was not open to the public or foreign observers, including the Swedish Embassy, which looks after American interests in the absence of diplomatic relations.
U.S. officials and others working for the reporters' release have said they have received no information about the defendants and even lacked independent confirmation about whether the trial had started.
There have been fears that the two woman were being used by Pyongyang as bargaining chips in its standoff with South Korea and the United States, which are pushing for U.N. sanctions to punish the nation for its latest nuclear test and a barrage of missile tests.
The journalists were arrested as they were reporting about the trafficking of women. It's unclear if they strayed into the North or were grabbed by aggressive border guards who crossed into China.
Gore spokeswoman Kalee Kreider said the former vice president has no comment. Calls to Alanna Zahn, a spokeswoman for the journalists' families, went unanswered and she did not immediately reply to messages.
The U.S. Embassy in Seoul did not immediately comment.
The sentences are much harsher than what many observers had hoped for.
Choi Eun-suk, a professor on North Korean legal affairs at the Institute for Far Eastern Studies at Kyungnam University in South Korea, had speculated that the reporters would likely be sentenced to more than five years but less than 10 years in a labor prison. Then the negotiations with the U.S. would begin, he said.
U.S. Secretary of State Hillary Rodham Clinton said Friday she was "incredibly concerned" about the plight of the two women. In working for their release, Clinton said she has spoken with foreign officials with influence in North Korea and explored the possibility of sending an envoy to the North, but suggested that no one would be sent during the trial.
Koh Yu-hwan, a North Korean expert at Dongguk University in Seoul, had said Pyongyang will likely free the reporters and treat their release as a goodwill gesture that should be reciprocated with a special U.S. envoy visiting the isolated state.
Another American who was tried in North Korea in 1996 was treated more leniently. Evan C. Hunziker, apparently acting on a drunken dare, swam across the Yalu River - which marks the North's border with China - and was arrested after farmers found the man, then 26, naked. He was accused of spying and detained for three months before being freed after negotiations with a special U.S. envoy.
The North Koreans wanted Hunziker to pay a $100,000 criminal fine but eventually agreed on a $5,000 payment to settle a bill for a hotel where he was detained.