Neater! Why didn't I think of that....

Dana DeLouis wrote:
Just some more options:

Sub Demo()
With ActiveCell
If .Comment Is Nothing Then
.AddComment "First Line" & vbLf
Else
.Comment.Text .Comment.Text & "More Lines" & vbLf
End If
.Comment.Shape.TextFrame.AutoSize = True
End With
End Sub

HTH :)