Pfizer is investing 100 million euro in two Irish manufacturing sites in Dublin and Cork.
77 million's being invested in the Grange Castle site in Clondalkin in Dublin - with the remainder going to Ringaskiddy.
There had been fears for jobs at the Ringaskiddy plant - where Viagra is manufactured - after the drug went off patent last month.
Pfizer says the expansion at the Grange Castle site will create 140 construction jobs over the next year - and the facility will be operational by 2015.
Pfizer announced in May that it was closing one of its plants at Little Island in Cork, with the loss of 136 jobs.
