Instead of deleting why not just filter on Friday...
However, if you insist, work from the bottom up

Sub deleteallbutfriday()
mc = "a" 'change to suit
For i = Cells(Rows.Count, mc).End(xlUp).Row To 5 Step -5
Rows(i - 4).Resize(4).Delete
Next i
End Sub


--
Don Guillett
Microsoft MVP Excel
SalesAid Software

"Ken G" wrote in message
...
I have a list of daily data that is one day per row, I need a macro to trim
it back from daily data to weekly data retaining only Friday's data for
each
week, so I need to delete 4 rows, skip a row and delete the next 4 rows
etc.
The list is currently about 400 rows. (Excel 2003)