Thank you, Lisa, for your response. At present I am forced to export to a CSV format, which is in turn imported to another database - I don't open the export file unless there's a problem. You're correct in saying that it's the CSV format stripping the leading zeros automatically, but I was hoping that if I added them as characters using an expression they would remian there in spite of the CSV format. I tried adding a PadL expression to the Zip Code field - to no avail. I also tried converting the field from characters to numbers on export and got an error. My next step would be to re-write a multi-step process to use a DBF instead of a CSV.