The trial will last for six months and will be evaluated by the Police Service of Northern Ireland in partnership with the College of Policing and Cambridge University.
The evaluation will help inform the introduction of body cameras for the entire PSNI.
They will be used by officers in Foyle, Strabane, Limavady and Magherafelt.
As part of the evaluation, not all officers will wear the cameras all of the time.
Superintendent Garry Eaton said the technology potentially offered a number of advantages for police and public alike.
"Officers can wear the cameras on their uniform and use it when they respond to a call or interact with members of the public.
"These contacts will be captured and can be downloaded and used in evidence where appropriate.
"They offer an opportunity to capture events as they happen and to store them so that they can be played back later to support victims and establish facts.
"Not only are the cameras useful from an evidence-gathering point of view, but if there is a disagreement between an officer and a member of the public, they can provide information quickly of what actually happened to establish facts."
As well as the PSNI, a number of services in Great Britain have also begun to deploy the cameras.
Supt. Eaton added: "The cameras will normally be attached to an officer's uniform at chest height. They are small and robust and have been designed for ease of use. Only minimal training is required.
"The cameras can record pictures and sound for up to two and a half hours, but would not normally be on all the time. They can be switched on and off by the user."
One of the areas for using the cameras will be domestic violence incidents.
Police in parts of County Londonderry and Tyrone have begun a pilot scheme to introduce the use of body cameras.