This review focuses on the aspects of biology of the elk (Alces alces) and red deer (Cervus elaphus) related to disturbance and barrier effect of highways. The information concerning home range size, migratory and dispersal movements and susceptibility to anthropogenic disturbances as well as examples of preferred wildlife passages was reviewed for both species. The disturbance and barrier effects of highways, or more precisely traffic, are different in each species. The red deer is the most susceptible to disturbances and it is even very difficult to encourage to use wildlife passages of any type. On the contrary, the elk, despite its large body size, is very adaptable and able to use relatively small under- and overpasses. Nevertheless, the use of wildlife passages could reduce the barrier effect of highways in both species. Location of wildlife passages should respect the structure of landscape and the passages should be protected from anthropogenic disturbances. The frequency of passages should be approximately one per each kilometer of highway in wooded landscape or one per three kilometers in open agricultural landscape. The minimum recommended width of wildlife overpasses is 40 m and the minimum index of clearance of underpasses is 1.7.