Thank you Petr, Gustaf and Gabor. Your help is much appreciated. I have tried: dataset[!duplicated(dataset[,-2]),] and it solves my problem. Thanks, Chris -- View this message in context: http://r.789695.n4.nabble.com/Remove-duplicated-rows-tp2023065p2065997.html Sent from the R help mailing list archive at Nabble.com.