The 25-year-old joined the team in 2018 from Cannondale-Drapac, where he'd spent two seasons, and said that he feels at home at Trek-Segafredo, and wants to continue to concentrate on time trialling and improving in one-day races.
"I was really happy when [general manager] Luca [Guercilena] gave me the opportunity to re-sign," said Mullen in a press release. "I love it in this team, and I think I really fit in well. They give me every opportunity and every backing that I feel like I deserve for the TTs. Everyone is always super understanding and super motivated when it comes to my opportunities.
"And obviously with the Classics team we have a really great group of guys; it would have been a shame to leave these guys behind. Over the last two years, we've developed a good friendship and really great working environment between Mads [Pedersen], Jasper [Stuyven] Koen [de Kort] and me. We all bond well and get the best out of each other," he said.
"In that sense, it made perfect sense for me to stay with the team and to continue to grow in this environment and to keep working on my future goals and ambitions, like being successful in TTs and one-day races, and riding Jasper and Mads deep into the finals of the cobbled Classics," Mullen continued. "From that point of view, it's the perfect place for me to grow."
Mullen again won the Irish national time trial championship this year, for the fourth time in his career, in which he's also twice been national road race champion, with his only other pro victory coming on the individual time trial stage of the 2018 Vuelta a San Juan in Argentina.
"For the next two years, I will hopefully continue on the path I have been on: I want to get a few more Grand Tours in me and continue focusing on TTs and being one of the super domestiques when it comes to the Classics with Jasper and Mads," he said.
"In the past two years, Ryan has proved to be a strong time triallist and a valuable team player for the Classics," added Guercilena. "We strongly believe in Ryan's capacities for the time trial and want to give him the chance to further develop them within our team. He fits really well in the team in general and has also found his place and role in the Classics team. For all these reasons, we are very happy to have him on board for two more years."