The move is in response to safety recommendations put forward by the National Transportation Safety Board following a December Metro-North derailment that killed four people in the Bronx, the MTA said.
"We will be systematically implementing recommendations put forward by the NTSB and other regulators to ensure the best practices are adhered to throughout the MTA family," MTA chairman Thomas Prendergast said.
The MTA, which runs both railroads, said it intends to put out a request for proposal. Prospective vendors will be asked to design and manufacture an on-board video recording system for its newest cars and all locomotives.
Transportation officials say the purpose of the cameras is to aid post-accident investigations and to deter behaviors that could adversely affect the trains' safe operation.
Both railroads also are working together to procure and quickly install positive train control technology, which is designed to automatically stop or slow a train before certain accidents occur, the MTA said.
The LIRR and Metro-North are the nation's busiest commuter rail lines, collectively averaging more than 580,000 customers per day in New York and Connecticut.