One way to improve the sustainability of pig production is by increasing the currently rather low protein deposition efficiency. The purpose of the study was to assess the variability and ultimately the potential in protein deposition efficiency and its impact on growth performance and carcass characteristics of Large White pigs. A growth performance experiment was conducted with 40 castrated male pigs from 23 to 112 kg body weight (BW). They were group-penned and offered the same crude protein reduced grower and finisher diets (80% of Swiss feeding recommendation) ad libitum. To estimate whole body protein and fat content, pigs were scanned by Dual Energy X-ray Absorptiometry (DXA) for lean and fat tissue weights at 52 and at 104 kg BW. Based on the protein accretion between the two scans and the respective individual protein intake, protein efficiency for each pig was calculated. The 12 pigs with the highest and the 12 pigs with the lowest efficiency were assigned to the H- and L-group, respectively. Despite being selected for protein efficiency in the finisher period, overall gain-to-feed ratio was greater in H-pigs. The whole body composition of the H- and L-pigs were similar at the first scan whereas fat content was lower in H- than L-pigs at the second scan. The lower whole body fat content was not reflected in leaner carcasses of H-pigs. This could imply that internal organs and/or the digestive tract contained less fat and more protein and ultimately the greater protein efficiency is due to more efficient deposition of dietary protein in the internal organs.