In the deadliest attack, gunmen stormed a small Iraqi Army outpost in the town of Dujail before dawn, killing 10 soldiers and injuring eight more.
Hours later, a car bomb struck a group of police recruits waiting in line to apply for jobs with the state-run Northern Oil Company outside the northern city of Kirkuk.
A police spokesman said seven recruits were killed and 17 wounded. He said all the recruits were Sunni Muslims and blamed the early morning attack on al Qaida.
The carnage even stretched into the country's south, where bombs stuck to two parked cars exploded in the Shiite-dominated city of Nasiriyah.
The blasts were near the French consulate and a hotel in the city, although the consulate did not appear to be a target of the attack.
Two people were killed and three injured at the hotel, and an Iraqi policeman was wounded at the consulate.
A string of smaller attacks also struck nine other cities, including Baghdad.
In the capital's eastern Shiite neighbourhood of Husseniyah, roadside bombs killed a policeman and a passer-by. Another eight people – including four soldiers – were injured.
The rest of the attacks were car bombs.
In Basra three people were killed and 24 hurt, while in Tal Afar two passers-by were killed.
Two car bombs in southern Maysan province killed five people and wounded 40 outside a Shiite shrine.