Thanks for replying, indeed works. I forgot to mention that I am looking for a 'transparent shading' s.t. the plot symbols are still visible on the shaded area. robert -- View this message in context: http://r.789695.n4.nabble.com/shade-area-between-ablines-tp2537352p2537479.html Sent from the R help mailing list archive at Nabble.com.