Four hundred devices have been purchased, at a cost of Â£1.5m.
Body Worn Video Technology, as it's known, is already in place in Derry City and Strabane District.
The cameras are clipped on to the top half of an officer's uniform and can provide eight hours of continuous recording.
Officers have been trained to tell people when they are being recorded.
Supporters of the scheme say the cameras will improve the quality of evidence that police officers can gather.
They will be particularly useful in assisting prosecutions in cases of domestic abuse, for example.
The roll-out follows on from a pilot scheme in Foyle in 2014-15.
Body cameras are routine in other parts of the UK and were first introduced about a decade ago.
Studies have found that they dramatically reduced complaints against officers by members of the public, by up to 93% in one case.
PSNI Chief Supt Chris Noble said: "Video evidence puts the victims of crime first.
"The pilot of this technology in Foyle district evidenced how Body Worn Video has the potential to improve the quality of evidence provided by police officers. It also increases the number of offenders brought to justice.
"The introduction of this new technology is the latest example of our commitment to these principles as we continue to work together with the community to keep people safe."
Police officers in Belfast will wear body cameras while on duty from Wednesday.