Microencapsulated pyrethroidal cockroach-controlling composition is provided, which has an excellent residual effect. The composition comprises phenylxylylethane and a pyrethroidal compound and is encapsulated in microcapsules formed of a polyurethane wall which have an average particle diameter of not more than 80 .mu.m, a wall thickness of not more than 0.3 .mu.m, and a value of the average particle diameter/wall thickness of 100-400.