Thanks, I found the function ecdf() which does the job. plot( ecdf( nvtpoints), col="BLUE", lwd=1, add=TRUE ) -- View this message in context: http://r.789695.n4.nabble.com/Add-a-density-line-to-a-cumulative-histogram-second-try-tp3666969p3669310.html Sent from the R help mailing list archive at Nabble.com.