American Type Culture Collection (ATCC) ^*

The most diverse collection of microorganisms, stem cell lines and animal and human cell lines.

http://www.atcc.org/

Cambrex

Cambrex Bioproducts has a state-of-the-art custom cell isolation laboratory that can provide tailor-made cells not commonly available from commercial sources. 

http://www.cambrex.com/

European Collection of Cell Cultures (ECACC)

Premier collections of authenticated cell cultures and purified DNA from cell lines.

http://www.ecacc.org.uk/

ScienCell

ScienCell Research Laboratories is a San Diego-based research-minded company providing the research community with the highest quality cell and cell-related products.

http://www.sciencellonline.com