Unum has moved its group protection policy administration to Mastek's Elixir system to integrate with broker and customer platforms more easily.
The roll out of Elixir with Unum will begin in early 2016 within Unum's Broker Services organisation.
Last month Unum increased its broker facing sales team's size and introduced its Broker Service teams to provide a single point of contact for brokers.
Elixir was adopted by Legal & General in 2011, having been trialled since December 2010.
Matt Fahy, chief information officer at Unum, said: "After a long due diligence process, Elixir proved to be the most sound and modern platform in the market.
"It will allow us to provide the best possible customer experience, enabling greater preparedness for future challenges. It will also support integration with other platforms in the marketplace."
Glenn Thompson, customer solutions director at Unum, said: "I am very excited to announce this next step in our programme to deliver market-leading customer service to our business partners.
"Building on a number of recent improvements within our business, this move will help to deliver best-in-class support for brokers, employers and employees."