We evaluated the effect of road mortality on population dynamics in Swedish badgers and estimated the critical level of road mortality that the population can sustain without decline. We used life table analysis and matrix population models to assess a stable age-structure and population growth. Estimates of age structure, fecundity, and sex ratio among road-killed badgers were obtained from 76 carcasses that we collected from public roads during April to September 2001, and from existing estimates in literature. There was no difference in fecundity or sex ratio between our sample and literature data, but the age structure among roadkills was skewed towards a higher proportion of adults and subadults than expected from the population model. The difference in growth rates and predicted losses between the population model and three alternative roadless models in which mortality was reduced by a age-specific proportion solely attributed to road traffic, suggested that losses due to road traffic respond for 12-13% of the postbreeding population. Since the population model predicted a nearly stationary growth rate, these estimated mortality levels were considered equivalent to the maximum sustainable loss. The predicted critical loss was similar to independent estimates of the present number of road-killed badgers in Sweden. Assuming the number of road-killed badgers being proportional to traffic intensity, and with regard to the quantified sources of uncertainty, we predict that between 1978 and 2049 nationwide road traffic will kill more badgers than the population can sustain without declining. Thus, this critical threshold may already be exceeded in areas of low badger density and of high traffic loads. We recommend taking greater concern for this species when planning and maintaining roads in such areas in Sweden.