The global insurance-based financial services group picked Fishburn after a competitive pitch process that is also believed to have included previous incumbent Hill & Knowlton, FD and M: Communications.
The Fishburn Hedges team, which begins work on the account immediately, is being led by director Jason Nisse.
Mani Pillai, Zurich's head of group media relations, UK, said: 'We look forward to working with Fishburn Hedges to build on Zurich's strong reputation within the insurance media, to reach out to a wider media audience across a variety of platforms.'
The brief does not incorporate analyst or investor relations, though Fishburn Hedges will support Zurich's in-house team in the UK around its financial statements.
Hill & Knowlton remains Zurich's retained global corporate agency.
Zurich was founded in 1872. Although based in Switzerland, it has more than 60,000 employees serving customers in more than 170 countries.