Abstract: A rubber composition for tire treads, comprising [I] 10 to 90% by weight of a styrene-butadiene copolymer rubber containing not more than 40% by weight of bound styrene and having bonded to a carbon atom of the rubber molecular chain at least 0.1 mole, per mole of the rubber molecular chain, of an atomic grouping represented by the following formula ##STR1## wherein: X represents O or S,R.sub.1 and R.sub.2 are identical or different and each represents an amino group or an alkyl-substituted amino group,R.sub.3 and R.sub.4 are identical or different and each represents a substituent other than the above-mentioned,m, p and q each represent O or an integer of at least 1,n represents an integer of at least 1, m+p=0-5, and n+q=1-5,and [II] 90 to 10% by weight of at least one rubber selected from the group consisting of styrene-butadiene copolymer rubber having a bound styrene content of not more than 40% by weight and polyisoprene rubber.