I think there might be an error on the following wiki page http://fedoraproject.org/wiki/Packaging/DistTag There are examples there like this: # If on Fedora 8, Requires: foo %{?fc8: Requires: foo} But if fc8 is defined you get an rpm error stating Unknown tag: Requires: foo After much fooling around I think I tracked the problem down to the fact RPM won't tolerate any white space in front of the "Requires:", I finally recalled that RPM will choke if it sees indentation in certain places in the spec file. The net effect of the macro on the wiki was that "Requires:" was indented by 1 space. It seems like it has to be: %{?fc8:Requires: foo} I will update the wiki but I thought I would sanity check my conclusion first. IMHO RPM's parsing is way too fragile, it took me a while before it occurred to me it was the space character causing the error. The error message wasn't very helpful either, did anybody else notice there were two spaces between the "Unknown tag:" and the "Requires" in the error message implying the tag was " Requires" and not "Requires"? John