ISLWYN MP Chris Evans added his voice to calls to preserve the Welsh Cavalry- which is under threat because of cuts to the defence budget.
Mr Evans joined MPs, including Newport East's Jessica Morden and Blaenau Gwent's Nick Smith for a rally in London last week.
Supporters of the regiment, officially known as the 1st Queen's Dragoon Guards, attended the rally in Parliament Square, before delivering a 6,000 name petition to Downing Street.
The regiment is thought to be under threat of being merged or axed following Government cuts to the defence budget, but Mr Evans questioned this, calling it "one of the oldest and most distinguished regiments in the British army".
He said plans to disband it would be a "massive blow to Wales", citing the large number of people it recruits not just from his Islwyn constituency but from all over Wales.
Mr Evans added: "The Welsh Dragoon Guards are one of the best recruited regiments in the armoured corps and disbanding it would reduce opportunities for young people all over Wales to serve in a named Welsh regiment."
The regiment, which dates back over 300 years is under threat of disbandment or amalgamation with another regiment as part of an upcoming strategic defence review- with job cuts possible as the Army is cut from 102,000 to 82,000 personnel by 2020.
Mr Evans said he is standing "full-square behind our guards" in the fight to preserve the regiment.