One camera will record images in the front while the other will capture what the suspect is doing in the backseat.
And in order to make sure audio is properly recorded, the officers will reportedly wear wireless microphones.
The footage is to be wirelessly transmitted to computers at police stations, the idea being that officers and suspects are protected from accusations, racial profiling and lawsuits.
It will cost about $5 million to install all 300. LAPD has 1,600 patrol cars. They may be equipped with video cameras later as the cost will be upwards of $25 million.
Authorities say they wanted to green light the video camera project before Police Chief William Bratton leaves his post.
His last day is scheduled for Oct. 31.
City News Service contributed to this report.