According to Westercon 67 Registrar Jordan Brown, 636 individual people attended Westercon 67 in Salt Lake City as members of the convention. 98 people bought memberships and did not attend (no-shows). 535 memberships were purchased in advance and 199 at the door. No breakdown of memberships between attending, supporting, and other classifications was available.
In addition to the 636 Westercon membership who attended, approximately 220 people from FantasyCon, a separate event held simultaneously across the street, checked in with Westercon 67 to take advantage of a cross-marketing offer whereby members of either event could attend the other. No figures are available of how many Westercon 67 members attended FantasyCon.