Mr Gethin said: "I am proud and delighted to have been elected to continue in office for the next three years. I'd like to thank all the clubs and affiliated organisations who supported me.
"As President I maintain close contact with players, coaches and administrators from all sectors of the game in Wales and that is a great honour.
"It has also been my pleasure to represent the Welsh Rugby Union within the international rugby environment and I look forward to continuing that role.
"I want to wish my opponent in this election, Howard Watkins, all the very best and I look forward to continuing our discussions about Welsh rugby at the earliest opportunity."
The Chairman of the Welsh Rugby Union, David Pickering, said: "Dennis Gethin has given the WRU great service so far as President and I am delighted that his success in this election means I will be able to continue to work closely with him and benefit from his sound advice."
Dennis Gethin was Secretary of the Welsh Rugby Union for five years from March 1998 to December 2002 and was elected as President in September 2007.
Now aged 64, as a player he was a Welsh Secondary Schools International in 1963 and won two rugby Blues at Cambridge in 1965 and 1966. He played his club rugby as a fullback for Seven Sisters, Swansea, Neath, Cardiff and Glamorgan Wanderers.
He is a qualified solicitor and became Chief Executive of Taff Ely Borough Council from 1982 until his retirement in 1996.
After his retirement he became Secretary and later Chairman of the Welsh Academicals and is now a Life Vice President of the club.