The National Union of Journalists (NUJ) said journalists voted overwhelmingly in favour of strike action.
It said almost 92% of members balloted backed action, showing their "anger and disgust over FT's broken promises".
The changes to pension arrangements follow the purchase of the FT three months ago by Japanese media group Nikkei for Â£844m.
The NUJ accused the Financial Times and Nikkei of failing to honour equivalent terms of employment promises made following the takeover of the newspaper group.
It said that on Monday, senior managers put forward new proposals to the union, which it said it would be considering before making a final decision over whether to call its members out on strike.
Steve Bird, NUJ representative at the Financial Times, said senior managers had already lost the trust of their staff including "most senior journalists".
He added: "We will be seeking talks with our new owners and expect a clear commitment to make good any shortfalls on our pensions."
A spokesperson from the Financial Times said that management was "disappointed" that the NUJ had not withdrawn the strike threat, despite ongoing consultations and what it called an "improved" offer over pensions.
"While we do not take lightly any discontent amongst our employees, we must find the right balance between individual benefits - those who voted in the ballot represent a small minority of staff - and the sustainable financial future of the FT, for the benefit of all," the FT spokesperson said.
Three years ago FT journalists voted to strike over what they considered unfair pay rise proposals following what they said had been several years of below inflation pay deals.
Journalists at the Financial Times have voted for strike action over proposed changes to their pensions.