To avoid errors if case sensitive:

Sub rwInsrt()
lr = Cells(Rows.Count, 1).End(xlUp).Row
For i = lr To 2 Step -1
If LCase(Cells(i, 1)) = "x" Then
Cells(i, 1).EntireRow.Insert
End If
Next
End Sub


" wrote:

I have a problem. How to insert a row below a cell that contains a
given sign? For example, I need to insert a new row below every cell
that contains x? X is in in every row in column A.