We investigated phagocytosis, complement, lysozyme, and immunoglobulins in domesticated sika deer (Cervus nippon) in the south of the Primorye Territory. We determined the physiological status of cellular and humoral links of nonspecific immunity depending on season, age, and sex. We ascertained considerable fluctuation of activity of the immunologic indexes according to seasons, which illustrates physiological adaptation of the sika deer to changing environmental conditions. Most of the nonspecific immunity indexes were maximum in autumn, the period when mortality is minimal (10.6% of loss of all animals a year). In addition to seasonal changes of immunobiological indexes of sika deer, differences due to age and sex were also apparent. So cellulose factors of the immune defense were more active at a mature age; and indexes of humoral barriers increased during aging, yet greater activity of resources ensuring an oxidative reparative process was observed when deer were young. This demonstrates that physiological systems function intensively at different stages of development of the deer. Male sika deer have greater nonspecific immunity parameters (intensity of phagocytosis, concentration of lysozyme, titre of hemolysin, and glutinins) than does. These are probably connected with the level of metabolic processes.