1. Data from experiments with growing pigs of Danish Landrace (n = 782) including measurements of nitrogen and energy balances were scrutinized in order to select observations in which maximum protein retention (RP) were expected. 2. The criterions for selection were based on intake of metabolizable energy and oxidation of nutrients and a total of 152 measurements in the live weight (LW) range from 2 to 120 kg complied with the criterions. 3. The selected material were used in a quadratic function of RP on metabolic weight (kg0.75) to describe the curve for maximum RP. 4. The function obtained was: RP, g/d = 11.55 x kg0.75 - 0.185 x kg1.50 with a maximum of 180 g/d at 98 kg LW. 5. The RP-values were compared with data from the literature with other races and the function seems well established to describe maximum protein retention in non-hormone treated or specific selected pigs.