Look at ?substitute, ?expression, and ?paste. The archives are dense with worked examples. Here's one example of a parameter in the title: param <- pi plot(1:100, log(1:100)) title(substitute(hat(theta) == param, list(param=param))) A search of the archives for "label points plot" turns up 100s of hits. http://cran.r-project.org/search.html HTH, Andy