A fluorine-containing pyrethroid metofluthrin is widely used recently in mosquito repellents. The urinary excretion kinetics of its metabolites was evaluated in rats to establish an optimal biomarker for monitoring metofluthrin exposure of the general population. After metofluthrin had been administered intraperitoneally to rats, the urinary excretion kinetics of the major metofluthrin metabolites was evaluated by moment analysis. The urinary excretion amounts of 4-methoxymethyl-2,3,5,6-tetrafluorobenzyl alcohol were estimated to be proportional to the absorption amounts over a wide exposure range. Urinary 4-methoxymethyl-2,3,5,6-tetrafluorobenzyl alcohol was considered to be an optimal biomarker for metofluthrin exposure.