... is the apply function what you are looking for? A=matrix(1,2,4) apply(A,1,sum) HTH Pete -- View this message in context: http://r.789695.n4.nabble.com/Element-by-Element-addition-of-the-columns-of-a-Matrix-tp3483545p3483628.html Sent from the R help mailing list archive at Nabble.com.