The surface of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) film in contact with poly(acrylic acid) (PAA) aqueous solution became wettable by excimer laser irradiation. The water contact angle of the PFA decreased from 106 degrees to 40-60 degrees by irradiation of KrF laser pulses (22.4-67.6 mJ cm(-2) pulse(-1)) with total irradiation energy of 100-200 J cm(-2). The increase in amount of rhodamine 6G, a basic dye, adsorbed on the irradiated PFA surface showed a good correlation with reduction of the contact angle. Surface analysis by X-ray photoelectron spectroscopy indicated extensive loss of fluorine atoms and increase of oxygen atoms, in addition to a C1s spectrum similar to that of PAA. The present results demonstrate the introduction of a carboxylic group onto the PFA surface through a novel laser-induced graft reaction of PAA.