Revenues at the business founded by the late Edward Haughey increased by 8.5% to £215.7m in the 12 months to the end of last July.
Numbers employed by the group during the year went up by 107 to 2,152. Staff costs increased from £60.29m to £61.86m.
A former Seanad member and chairman of the group, Mr Haughey died in March 2014 in a helicopter crash in Norfolk, England, along with three other people.
At the time of the crash, the 70-year-old was the North’s richest man, with his personal wealth estimated to be around £650m.
The accounts show that the group recorded pre-tax profits of £21.62m, last year, after exceptional costs of £8.9m relating to the impairment of assets and losses from the disposal of a fixed asset.
The pre-tax profit also takes account of exceptional gains of £5.8m relating to the receipts from Mr Haughey’s estate relating to the past use of group assets, and interest charges of £1.7m.
The accounts also show that Norbrook made political donations of £200,000 during the year.
In the accounts, Norbrook’s directors said the business — as of the middle of last year — remained “well-positioned to capitalise on a number of commercial opportunities within the animal health industry” adding that they were confident of continued revenue and earnings growth.