Density dependent effects of food limitation on productivity have been documented for >12 species of large ungulates. In wild reindeer (Rangifer tarandus) a decrease in recruitment rate and adult female body size (although not in adult survival rate) develops in response to increasing population densities and is caused mainly by winter food limitation. This population response was used in modeling the maximum sustained yield (MSY) based on productivity curves in terms of annual biomass production/km2 or numerical abundance. The fit of 2nd-order polynomials was used to test for nonlinearity in the relationship between density and dynamics. The production curves peaked close to 50% of the ecological carrying capacity (K), suggesting a response of the type theoretically predicted for large mammals, but the biomass production peaked at a lower population density. In management terms the 1st-order derivatives from the productivity equations indicated a MSY at 1.75 animals/km2 of gross habitat, whereas numerical abundance peaked at 2.3. These results were shown for a population where winter range = total range x 0.12.