Khalid al-Attar, who worked for al-Iraqiya television, was abducted from a Mosul neighbourhood by unidentified armed men and found shot to death on Friday, the state-funded station said.
Paris-based Reporters Without Borders said al-Attar's death was the ninth killing of a journalist in Mosul, Iraq's third-largest city 360km northwest of Baghdad.
The organisation called on Iraqi and US authorities to investigate, saying Mosul has become "Iraq's most dangerous city for the press after Baghdad".
Mocking the government
Al-Attar, 43, worked for a satirical programme that poked fun at the government's perceived carelessness and inability to deal with major issues in the country, including frequent water shortages and power cuts.
There have been 61 journalists killed in Iraq since the war began in March 2003, according to Reporters Without Borders.
An Iraqi special correspondent working for Knight Ridder Newspapers was shot on 24 June as he approached a US-Iraqi military patrol.
It appeared that a US sniper shot him, but Iraqi soldiers in the area at the time also may have been shooting, the California-based newspaper company said.