Abstract: A locking slide device for use in a double-hung window assembly wherein one or more sash are adapted to tilt inwardly about a pair of pivot pins located at the lower portion of the sash. The pivot pins are received in carrier slides which are adapted to carry the sash for guided vertical sliding movement, the carrier slides being received in vertical guide channels defined by jamb liners. The carrier slides are also connected to counterbalance means such as helical springs. Each carrier slide has a groove that receives a vertical rib formed in the guide channel and a cylindrical roller with a horizontal axis is carried in a roller slot within the carrier slide for selective movement into locking engagement with the rib. The cylindrical roller is engaged by one of the pivot pins whenever the sash is in its normal vertical position relative to the jamb liners.