Centocor is a biotechnology company that was founded in Philadelphia in 1979 with an initial goal of developing new diagnostic assays using monoclonal antibody technology.

In 1982 Centocor developed their first FDA-approved product—a diagnostic test used to detect the rabies virus, and in that same year transitioned into a publicly traded company. Subsequently, the company moved to a larger facility in Malvern, Pennsylvania (a North West suburb of Philadelphia). In 1984, Centocor opened an overseas plant in Leiden, the Netherlands.

Eighteen years after its foundation, (in 1997), Centocor achieved its first year of operating profitability. In 1998, Centocor divested itself of its diagnostic division and launched its top-selling monoclonal antibody Remicade (infliximab) for its first FDA approved indication in Crohn's Disease. In 1999, Centocor became a wholly owned subsidiary of Johnson & Johnson, the worldwide manufacturer and marketer of healthcare products. Subsequently, Remicade's market has expanded with approvals for rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, ulcerative colitis, and pediatric Crohn's disease. Remicade was approved for plaque psoriasis in September 2006.

Centocor also markets ReoPro® (abciximab)a biologic agent indicated as an adjunct to coronary angioplasty (PTCA)

Since being acquired by Johnson and Johnson, Centocor has increased its annual sales from approximately $500 million to more than $2 billion. During the same period, research and development investment increased from $75 million to more than $300 million.

In 2004 Centocor purchased a new manufacturing plant in St. Louis, Missouri, and is currently opening a new manufacturing facility in County Cork, Ireland. The Dutch plant has been expanded substantially with a $250 million investment in additional production facilities, which were opened in 2006.