This appears to be a reasonably complete list (refer to the YC sheet): http://spreadsheets.google.com/ccc?key=0AkkhSN3vaY4jdF90b1l1Vnl5NmZjaTBNQWlJYVozMEE&hl=e

This appears to be a reasonably complete list (refer to the YC sheet): http://spreadsheets.google.com/ccc?key=0AkkhSN3vaY4jdF90b1l1Vnl5NmZjaTBNQWlJYVozMEE&hl=en http://spreadsheets.google.com/ccc?key=0AkkhSN3vaY4jdF90b1l1... According to that list, 14 are dead. That might be an underestimate, as BusinessWeek's Top Angels in Tech list puts the number of dead YC startups at about 21.