Abstract: A vertical guide for a roll-up type screen as used on windows and doors can be used either inside or outside as desired. The guide is placed in opposing relation on the left and right sides of the window or door and includes a first U-shaped retainer which is frictionally attached to a base. The guides allow the user to purchase screens for windows having various width openings since the guides can be adjusted horizontally to seal the edges of the screen and prevent insect and debris infiltration.