Mosaic creator and Netscape co-founder Mark Andreessen and his wife Laura Arrillaga-Andreessen announced a $27.5 million gift to Stanford Hospital and Clinics Friday to build a new state-of-the-art emergency department.

The new department on the Stanford Medical Center campus, to be named after the couple, will be more than double the size of current emergency facilities

This is the first major philanthropic commitment for the couple, who said they literally began discussing it the day they became engaged in 2006.

Andreessen joined the Stnaford Hospital and Clinics board of directors a year ago. Arrillaga-Andreessen teaches courses in strategic philanthropy at the Stanford Graduate School of Business, where she is a faculty member, and is founder and chair of SV2: Silicon Valley Social Venture Fund.