Abstract: A wireline set baffle for positioning in a well casing after the well casing has already been placed in a wellbore. The apparatus comprises a baffle and a setting or running tool engaged with the baffle and adapted for positioning the baffle at a predetermined location in the wellbore. In one embodiment, a lock ring may be used to lock the baffle to the casing at a predetermined location, and in another embodiment, collet fingers on the baffle may be used to engage the casing. The lock ring may be initially held in a non-engaging position by a lock ring retainer or shear pins. The collet fingers may be initially held in a non-engaging position by a cover which is disengaged from the collet fingers by a blasting cap. Engagement may be with an inner surface of the casing or a recess defined at a casing joint. A method of using the wireline set baffle is also disclosed.