Ben - I'm sorry, you're right! The following website shows how to make a volcano plot using ggplot2. http://bioinformatics.knowledgeblog.org/2011/06/21/volcano-plots-of-microarray-data/ Enjoy! Anna -- View this message in context: http://r.789695.n4.nabble.com/r-help-volcano-plot-tp3792651p3795847.html Sent from the R help mailing list archive at Nabble.com.