The 48 hour strike is the first of two being held in protest at plans to close ticket offices on the network and cut hundreds of jobs.
London Underground says some of the job cuts will be achieved by axing unfilled posts with others met through voluntary redundancy.
In 2008 Mayor Boris Johnson opposed plans put forward by his predecessor to close 40 ticket offices in the wake of Oyster’s success, insisting they still provided a valuable service for commuters.
However he now says the continued take-up of Oyster and imminent introduction of contactless fares on the Tube, DLR and London Overground means they’re no longer needed.
The RMT says the closures and job losses will lead to a worse service and warn some disabled passengers may be unable to get the help they need to complete their journey.
Tube bosses deny the claims and insist all stations will remain staffed during opening hours and that all passengers will have access to assistance when needed.
RMT members will hold a 48 hour strike from 9pm on Monday April 28th followed by a three-day strike 9pm on Monday May 5th.
LU says it will run as many services as possible but warns the strike will cause disruption.
It advises passengers to complete their journeys on Monday evening before the start of the strike and warns of disruption on Tuesday and Wednesday “when Tube services will start later and finish earlier than normal”.
In a statement LU says “it is not possible to say exactly what services we will be able to run” but suggests it will be able to run partial services on all lines except the Waterloo & City line.
Passengers are being urged to plan alternative routes and to check before they travel at tfl.gov.uk and by following @TfLTravelAlerts, @TfLTrafficNews and @TfLBusAlerts on Twitter.