Working with the head of YMCA in England, Kevin Williams, Industry @ Saatchi will bring 150 YMCA branches together.
It aims to help them recognise common cultural and business objectives that run through the organisation. Industry @ Saatchi will then develop a strategy for future growth for the YMCA.
Vicky Moffatt, the managing director of strategy for Industry @ Saatchi, said: "We are really interested in this type of strategic challenge in the cultural change space.
"The research and development lab approach is perfect for the YMCA because of the complex stakeholder alignment challenges.
"We also have access to YMCA's research capabilities, which will be a real asset for our other clients, helping them across notoriously hard-to-reach consumer groups and diversity groups in particular."
Williams commented: "Industry @ Saatchi is bringing us top-level talent to help with this critical organisational challenge. We are already seeing great results and this could not be more important for us in the long term."