yet the code you've supplied is looking in Col C not A.In column A I have number accounts
Sub add_rows()
'Modified 6/11/18 10:15 AM EDT
Application.ScreenUpdating = False
Dim Lastrow As Long
Lastrow = Cells(Rows.Count, "A").End(xlUp).Row
Dim accnum As String
accnum = InputBox("Enter account number")
For i = Lastrow To 2 Step -1
If Cells(i, 1).Value = accnum Then Rows(i).Insert
Next
Application.ScreenUpdating = True
End Sub