Abstract: An adjustable roofing jack (10) for securing a scaffold (22) of a selected size for roofers to prevent falls and other dangers associated with working on an inclined surface, and especially high-pitched roofs. The adjustable roofing jack (10) includes a frame (12) for engaging the surface of the roof (24). The frame (12) includes an extended portion (34) for engaging one side of a scaffold board (22). An opening (36) is defined by the extended portion (34) for the receipt of a nail, screw or other conventional fastener (38) to prevent the scaffold board (22) from rotating axially. Slotted openings (42) are defined by the frame (12) for receiving at least one selected fastener (40) to secure the adjustable roofing jack (10) to the roof (24). A scaffold support (16) is attached to the frame (12) for supporting a scaffold board (22) of a selected width. An adjuster (18) is provided for altering the effective width of the scaffold support (16).