The mechanical attachment of photovoltaic (PV) arrays to rooftops presents a number of unique and challenging issues for system designers and installers. With a resurgence of roof-mounted PV installations due to increasing duel costs and decreasing PV system prices, the Florida Solar Energy Center (FSEC) has accelerated its investigations of array mounting strategies, with the objectives of identifying key performance and cost parameters from a systems engineering perspective. Two principal classifications can be defined for rooftop PV array mounting systems: building-integrated (BIPV) and building-attached (BAPV) or standoff designs. The various attachment methods within these categories each have pros and cons that affect the labor and cost associated with the install and the system performance. An overview and assessment of some existing rooftop PV array attachment methods or mounting approaches, and their advantages and disadvantages with respect to key design criteria are presented to assist designers and installers in the selection of the appropriate method for a given project.