The event was held at a stadium in Pyongyang and was attended by Kim Jong Un, the late leader's youngest son who took over as head of the Communist country, and other top officials, the South Korean Yonhap News Agency reported.
"A national memorial service was held with solemnity here to mark the first anniversary of demise of leader Kim Jong Il," the North's Korean Central News Agency said in an English dispatch.
"He strengthened the Korean People's Army into the matchless revolutionary army of Mount Paektu, led the unprecedented standoff with imperialism and the U.S. to one victory after another and made the Democratic People's Republic of Korea a world-level military power and legitimate nuclear weapons state," Kim Yong-nam, the president of the Presidium of the Supreme People's Assembly, said during the ceremony.
Kim Jong Il died of a heart attack on Dec. 17, 2011.
The ceremony commemorating his death came just days after the North's successful long-range rocket launch on Dec. 12.