Provided is a compound that is useful for the prevention of and as a remedy for diseases attributable to abnormal plasma uric acid levels. The invention pertains to a biaryl isonicotinic acid derivative represented by formula (I), and prodrugs or salts thereof, which has xanthine oxidase and URAT1 inhibitory activity and is thus useful for the prevention of and as a remedy for diseases attributable to abnormal plasma uric acid levels. In formula (I), ring A is an aryl or a heteroaryl, R1 is a cyano, a trifluoromethyl, etc., R2 is H, fluorine, a C1-6 alkyl, a C1-6 alkoxy, etc., R3 is fluorine, chlorine, a hydroxyl group or a group represented by U-Y-Z (U represents a single bond or -O-, Y represents a C1-6 alkylene, etc., Z is H, a halogen, a hydroxyl group, a methoxy group, etc.), and n is 0-3.
