Almac are to spend around £5 million on building a new laboratory and office at their headquarters in Seagoe Industrial Estate.
Around 170 existing employees will be transferred to the new building, many of whom are chemists and analysts involved in supporting drug research, development and manufacture.
The extension is part of a £27 million global expansion which will see the total number of employees reach 5,000 by 2017.
About 60 per cent of the workforce is based in Craigavon.
The bulk of the investment - £20 million - will be spent at the US headquarter site in Souderton, Pennsylvania to expand its existing 240,000 sq ft facility as well as leasing a 26,000 sq ft office in nearby Lansdale.
A further £2 million will be invested in the development of the Arran Chemical Company in Athlone, acquired by Almac last year.
Alan Armstrong, chief executive of the Almac Group, said, “Due to significant industry demand for our services it is essential we build capacity and increase headcount to ensure we continue to compete at a global level.
“This year we are celebrating our twentieth year in the US and we are excited to make a further commitment within the Pennsylvania State and throughout North America.
“We are also delighted to announce our further expansion plans across Europe as we continue to build upon our tremendous global success.”
The plans are aimed at facilitating growth of the Almac Sciences business, which is vital to meet ongoing demand for its API and chemical development services.
Global headcount within this business unit alone is expected to reach over 500 by next year - more than double its figure three years ago.
The announcement has been welcomed by Upper Bann MP David Simpson and MLA Carla Lockhart who described it as a “huge boost” to the local area. They said, “The continued investment of Almac proves that we have a highly skilled workforce, with a strong talent pool which is highly attractable. The announcement represents good news for our local economy and will create further jobs in our construction industry.”