Try a formula like

=IF(C1="",A1,A1&B1)


--
Cordially,
Chip Pearson
Microsoft MVP - Excel
Pearson Software Consulting, LLC
www.cpearson.com



"Jack" wrote in message
...
Hello. I have worksheet in which I have data in the A column,
data in the B
column, and (sometimes) in the C column. I'm having trouble
with the correct
formula. I want to put in the D column something that states
If "C1" is
blank then enter A1. And If "C1" is not blank, then
concatenate A1 and B1.

I hope that makes sense and thank you in advance.