The present invention relates to polyorganosilylated carboxylate monomers or polymers thereof, comprising a polyorganosilylated carboxylate monomer of the general formula (I) or a polymer thereof, ##STR00001## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 each independently represent hydrogen, alkyl, alkenyl, alkynyl, alkyloxy, aryl, aralkyl or halogen radical optionally substituted by one or more substituents independently selected from the group comprising alkyl, aralkyl, aryl, hydroxy, halogen, amino or amino alkyl radicals, R.sup.7 represents hydrogen, alkyl radical or --COOR.sup.9, wherein R.sup.9 represents an alkyl group, R.sup.8 represents hydrogen, alkyl radical or --CH.sub.2--CO.sub.2--(SiR.sup.4R.sup.5O).sub.n--SiR.sup.1R.sup.2R.sup.3, and n represents a number of dihydrocarbylsiloxane units from 3 to 20. The invention also relates to the use of these monomers or polymers as coating compositions including antifouling coating compositions.