Insert and If...then...Else field
{ IF { MERGEFIELD afieldthatmaybeblank } = "" "{ MERGEFIELD nextmergefield"}
"{ MERGEFIELD afieldthatmaybeblank } { MERGEFIELD nextmergefield }" }

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Hope this helps.
Please reply to the newsgroup unless you wish to avail yourself of my
services on a paid consulting basis.
Doug Robbins - Word MVP
> Word 2003 mail merge leaves a blank if an instance for a field does not
> contain a value. this leaves awkward blank spaces in the merged documents
[quoted text clipped - 10 lines]
>
> http://www.microsoft.com/office/community/en-us/default.mspx?mid=3e6713ee-d710-4
89a-98ea-1f5dc35644b5&dg=microsoft.public.word.mailmerge.fields