The two acquitted police officers faced charges of shooting dead an anti-regime protester in November 2011, AFP reported.
In a separate case the court cut a 7 year prison sentence of another officer to six months. The policeman was sentenced in January for beating to death a Shiite protester.
In addition the court confirmed 5 year jail terms of 19 Shiite anti-regime protesters, which were charged each with attacking police forces.
This comes in the wake of clashes on Friday between police forces and thousands of Shiites in the village of Diraz, west of the capital Manama.
The protesters threw stones at hundreds of riot police who fired tear gas and water cannons, a witness said as cited by Reuters. The violence continued for about an hour before the police dispersed the crowd.
The protests were prompted by an unauthorized raid by security forces on a home of a top Shiite cleric Ayatollah Sheikh Issa Qassim on May 17.
Following the incident the main Bahraini opposition group Al-Wefaq announced on Wednesday that it would withdraw from reconciliation talks with the government for two weeks.