Another 150 jobs are lost at the shipyard Babcock in Rosyth, the company has confirmed.
The yard is currently working on the second of two aircraft carriers for the Royal Navy.
In November 2017, the yard announced 250 redundancies, followed by a loss of 150 jobs in March last year.
A Babcock spokesperson said it "expected the loss of about 150 specific roles".
He said it was assessing the company's current workload and medium-term opportunities and said the roles were no longer needed in line with the phasing out of the aircraft carrier program.
& # 39; Kick in the teeth & # 39;
The unite union said the news was a "kick-in-the-tooth" for the Scottish economy and a "world-class staff who worked tirelessly to build the two new aircraft carriers of the United Kingdom".
Steve Turner, the general secretary of the manufacturing union, said: "The men and women whose skills the two new leading aircraft carriers in the United Kingdom built at Rosyth run the risk of being lost to a generation in one fell swoop to the Scottish economy and UK shipbuilding.
"The announcement of job losses will shake the hordes of shipyard workers across the UK, which have endured the threat of leaving the Mersey and the closure of Devon's Appledore shipyard in recent months."
He warned that the job loss at Rosyth could "turn into a flood", leaving the industry with a gaping skill gap, unless the British government began delivering a shipbuilding strategy that guaranteed the new auxiliary ships of the Royal Navy were built in British shipyards. British steel.
He also called on the government to work with the type 31st frigate for exports around the world.
& # 39; New challenges & # 39;
GMB Scotland said that Rosyth needed large-scale shipbuilding to realize its full potential.
The trade unionist Gary Cook of the union said: "These layoffs emphasize the urgent need for the British government to ensure that the three Royal Fleet Auxiliary (RFA) ships are built in British shipyards, including Rosyth."
A Babcock spokesperson said that the prospects for business at Rosyth remain "strong with great opportunities".
"Last year we started the process of reshaping our company to remain competitive and to face new challenges, now that the large-scale design and construction phase of Queen Elizabeth's career program has reached completion," he said.
- The gigantic aircraft carriers of the UK
He added: "Our employees remain our priority during this process, we understand how troubling this can be and will work closely with those involved and our trade union representatives during this consultation period to relocate or relocate as many employees as possible within our broader organization. those who want to take this opportunity to continue. "
Unite plans to seek an urgent meeting with the Scottish government to put pressure on the British government on future contracts.
Minister of Affairs, Jamie Hepburn, said that the Scottish government would support those affected by dismissal after the "extremely disappointing news."
& # 39; Secure jobs & # 39;
"Scottish Enterprise, the Scottish corporate agency, is working to support the company in diversifying to other industries," he added.
"We welcome the company's commitment to relocate or relocate as many people as possible, protecting jobs."
A spokesman for the Ministry of Defense said: "We continue to invest in British shipbuilding, as shown by our Type 26 and Type 31e programs.
"The Babcock Rosyth yard has played a key role in our Queen Elizabeth Class carrier program and last month he received a $ 5 million contract for the maintenance of HMS Queen Elizabeth later this year."
The Queen Elizabeth Class (QEC) sailing program of £ 6.2 billion saw the construction of the HMS Queen Elizabeth and HMS Prince of Wales at seven locations for the last works in Rosyth. These are the largest warships that have to be built for the Royal Netherlands Navy.
HMS Queen Elizabeth has already underwent sea trials while HMS Prince of Wales will start testing later this year.