Bok lock extends stay in Ireland
Prior to joining Ulster at the beginning of last season, the 32-year-old played in Super Rugby for the Lions and the Sharks, and earned his solitary Springboks cap in the 2013 Rugby Championship against New Zealand.
Since arriving in Belfast, the 120kg lock has played a central role for Ulster registering three tries in his 42 appearances to date. He started 26 of Ulster's 30 games last season in the Pro12 and European Rugby Champions Cup and he has started 15 games of 17 games this season, highlighting his importance for the side.
Regarded as one of the squad's leaders, van der Merwe stepped in to captain the side on occasions last season in the absence of regular skipper Rory Best. He has also earned a reputation as one of the best line-out operators in European rugby and led the way for successful line-out takes in last season's PRO12 campaign.
"I'm really pleased to sign on for another year with Ulster, said Van der Merwe. "I've thoroughly enjoyed my time here and it was an easy decision for me and my family to take. We have felt very welcome from the moment we arrived and that is down to everyone involved in Ulster Rugby; the players, the management team and the supporters.
"This season has been a bit of a transition with Les [Kiss] coming in, but I'm really excited to be part of that the squad's growth over the next 18 months. The challenge for us is to keep improving and pushing to achieve silverware, and I'm confident that we'll continue to develop our game under Les and the other coaches.
"I have tried to bring some of my experience to the group and help some of the younger players. It's been encouraging for me to see some young forwards come through and make their mark in Europe and in the Pro12, which augers well for a successful Ulster team in the future."
Les Kiss, Ulster's Director of Rugby, welcomed the news that van der Merwe would be at the club next season.
"To have Franco stay for another season is a fantastic boost for Ulster," said Kiss. "His professional approach and the standards that he sets have been integral to the development of the young players coming through, such as Kyle McCall, Alan O'Connor, John Donnan and Stephen Mulholland.
"He is also an excellent club man, who contributes in such a positive way to the environment we are creating here. His durability is outstanding and his line-out expertise speaks for itself. Along with new signings Kieran Treadwell and Rodney Ah You, he will play an important role as we build and strengthen our forward pack for next season."
