Typhoons and torrential rain have damaged 5,000 homes and left more than 60,000 people homeless.
South Pyongyang province suffered the biggest lost of life. More than 30,00 hectares of land have been submerged.
North Korea is often hit by severe floods. Its poor economy leaves it ill-equipped to deal with the fall-out.
The KCNA website said “big human and material losses” had been caused between 18 and 24 July.
Around 300 public buildings and 60 factories had been inundated or collapsed, the news agency added.
Last year summer floods and a bitterly cold winter led to chronic food shortages, prompting Pyongyang to appeal for international aid.
The United Nations has forecast that three million North Koreans would need food aid this year.
For 66 years North Korea has been governed by a secretive dynastic regime, which has remained isolated from the international community.
Kim Jong-un, who became leader after the death of his father Kim Jong-il late last year, so far seems to be adopting a different approach to leading North Korea.
But relations with the West remain strained over its nuclear programme and accusations that Pyongyang violated UN resolutions in April by testing long-range missiles.