How do I Concatenate but keep Colour Formatting in Excel?

Edit: this is best handled with VBA not conditional formatting.

What kind of 'colour formatting'? Each cell to retain its formatting, even if different from the other cell(s), in the concatenated result? Or....?

You can easily concatenate the cells but retaining the formatting in the destination cell you will have to do manually unless you have some kind of conditional formatting on the cells that you can have applied to all the cells including the destination cell (the cell with the concatinated cells).

If you are using Excel 2007, you can select all the cells involved and apply two conditional formats.

Click on Conditional format, choose new format, then click on Cells that contain. Cell Values that contain, Between, a and z. Repeat this and instead of between a and z put -9999999999 and 99999999999 (whatever numeric values are within reason for the data) and format the same as the alphabetical conditional formatting.