i found a way :-) data<-merge(data,project,by.x="PJ_ID",by.y="PROJ_ID",all.x=TRUE) perhaps this can help someone Mat -- View this message in context: http://r.789695.n4.nabble.com/match-a-complete-data-frame-tp4658250p4658252.html Sent from the R help mailing list archive at Nabble.com.