Norbrook Holdings, the Newry-based pharmaceutical firm, increased its pre-tax profit by 36% to £49m in 2017.
The performance was achieved on turnover of £272m, which was up by 14%.
That was helped by the depreciation of the pound - at a constant exchange rate, turnover would have been up by 5%.
The firm produces veterinary medicines and is one of Northern Ireland's biggest exporters.
Chief Executive Officer Liam Nagle said it had been a "solid year" with new products helping to drive business, particularly in the US.
Norbrook has traditionally had a strong position in medicines for farm animals, but is now targeting growth in the pet market.
Mr Nagle said a chewable anti-inflammatory tablet for dogs is a particular support for growth plans in the US.
Sales in the pet market were up by 20%, while the farm animal market was up by 12%.
Aside from new product launches, Mr Nagel said the firm had "invested significantly" with:
- A second new laboratory facility
- Upgrades to the manufacturing capability
- Continued spending on IT
Capital investment amounted to £16.4m, bringing the total invested in two years to more than £26m.
Norbrook was founded by Lord Ballyedmond, who died in a helicopter crash at his estate in Norfolk in 2014.
His family continues to own the company.