Oh, I get it. I wasn't paying attention!

You'll be needing a subquery then...
VB Code:
  1. strQuery = "SELECT Surname & Chr(44) & Chr(32) & Forenames " & _
  2.           "AS FullName, IIF(IsNull(RegMem.MemID), ""N"", ""Y"") " & _
  3.           "AS Present From Members LEFT JOIN (SELECT MemID FROM RegMem WHERE SDate = #" & Format(#7/4/2005#, "yyyy-mm-dd") & "#) RegMem " & _
  4.           "ON Members.MemID = RegMem.MemID
I doubt if that is syntactically spot on, but you get the idea?