The growth rate of farmed European wild boars (Sus scrofa L.) is perceived to be very slow. However, there is no available information on the genetic potential of these animals in terms of potential lean tissue growth.The aim of the study was to determine the maximum capacity for protein deposition (operational PDmax) in wild boars under controlled environmental conditions. Four diets were formulated containing different levels of digestible energy (DE): 2.2, 2.4, 2.6, and 2.8 Mcal DE kg-1. All of the diets contained at least 5 g lysine per Mcal DE. Twenty purebred wild boars from a commercial farm of the same age (± 4 d) and with an initial liveweight of 27 ± 0.50 kg (mean ± standard error of the mean) were used in the study. At the beginning of the study (day 1), four animals were sacrificed and the carcasses were frozen without the digestive tract contents. The remaining animals were divided in foursomes and received each of the four diets over a 28-d period; they were then sacrificed and the carcasses were frozen without the digestive tract contents. All of the carcasses were ground and analyzed for DM, crude protein, ether extract, and ash. Protein deposition of the animals sacrificed on day 28 was determined as the difference between crude protein content estimated for the animals on day 1 using data from the animals sacrificed on day 1 and protein content of animals sacrificed on day 28. It was not possible to determine PDmax due to the genetic heterogeneity of the animals. Further studies on PDmax in wild boars must be carried out following genetic selection and breeding to produce more homogeneous animals.