This season the Galway-born back rower has played in nine out of 13 games so far, including a fantastic performance in the historic 16-14 win over Toulouse in round 3 of the Heineken Cup.
Muldoon captained Connacht for both the 2009/10 and 2010/11 seasons and this year his leadership skills saw him being named as one of three club captains.
With three international caps to his name, he was last called up to the Ireland squad during the 2012 GUINNESS Series. Unfortunately, his campaign was cut short when he was forced off with an injury during the second half of Ireland XV's non-cap international against Fiji.
The 31-year-old from Portumna shows no sign of slowing down on the pitch and remains a frontline player for Connacht team.
Speaking about the latest contract extension in the squad, Connacht head coach Pat Lam said: "Everyone knows that John is a true Connacht man. He is so respected as a rugby player and as a person.
"His character means that he is very influential on and off the field and it's a real boost for Connacht Rugby knowing that he's going to be here for another two years.
"John is a true professional in everything that he does and someone you want the other players to follow. He demands high standards from himself and everyone around him and commands his position on the field.
"The thing that impresses me most about him is that for someone who has played at the highest level, he's constantly striving to improve his game every day. This is reflected in his performances this season.
"It is fantastic that he's signed on again and I'm delighted with the chance to continue working with him."
Muldoon added: "I am delighted to be on board with Connacht for another two years. I've been involved with the province for over 12 years now and there have been so many positive changes around the place.
"This is where I'm from and I have so much pride in every game I play for the province. I believe we're building something special here and I'm excited to be a part of it."