An adhesive composition, especially suitable for a two-part adhesive system curable via free radical polymerization comprises; (A) (meth)acrylate ester monomer; (B) chlorinated elastomeric polymer; (C) core-shell impact modifier; and (D) urethane (meth)acrylate oligomer. Example adhesive compositions include urethane (meth)acrylate oligomer (D) derived from (i) a di- or higher isocyanate having at least two isocyanate groups which differ in reactivity; (ii) a chain-extending reagent which has at least two groups selected from hydroxyl and/or amino groups, each capable of reaction with an isocyanate group of (i); (iii) a hydroxymethacrylate component or hydroxyacrylate component. Also urethane (meth)acrylate oligomers, suitable for use in adhesive compositions, and derived from: (i) a diisocyanate having two isocyanate groups which differ in reactivity; (ii) a chain-extending reagent which is a polyether polyol selected from ethoxylated and propoxylated derivatives of tri- and tetra-functional polyols; and (iii) a hydroxyl (meth)acrylate selected from polyethylene glycol (meth)acrylate and polypropylene glycol (meth)acrylate, are disclosed.