The low velocity impact response of plain autoclaved aerated concrete (AAC) and FRP/AAC sandwich panels has been investigated. The structural sandwich panels composed of a FRP/AAC combination have shown excellent characteristics in terms of high strength and high stiffness-to-weight ratios. In addition to having adequate flexural and shear properties, the behavior of FRP/AAC sandwich panels needs to be investigated when subjected to impact loading. During service, the structural members in the building structures are subjected to impact loading that varies from object-caused impact, blast due to explosions, to high velocity impact of debris during tornados, hurricanes, or storms. Low velocity impact (LVI) testing serves as a means to quantify the allowable impact energy that the structure is able to withstand and to assess the typical failure modes encountered during this type of loading. The objectives of this chapter are: to study the response of plain AAC and CFRP/AAC sandwich structures to low velocity impact and to assess the damage performance of the panels; to study the effect of FRP laminates on the impact response of CFRP/AAC panels; to study the effect of the processing method (hand layup versus VARTM) and panel stiffness on the impact response of the hybrid panels. Impact testing was conducted using an Instron drop-tower testing machine. Experimental results showed a significant influence of CFRPs laminates on the energy absorbed and peak load of the CFRP/AAC panels. Further, a theoretical analysis was conducted to predict the energy absorbed by the CFRP/AAC sandwich panel using the energy balance model, and the results found were in good accordance with the experimental ones. © 2013 Woodhead Publishing Limited All rights reserved.