The authors present the results of study of arbidolum therapeutic-and-prophylactic effectiveness in acute respiratory viral infections (ARVI) under conditions of military staff with determination of economic expediency. Coefficient of effectiveness of arbidolum prophylactic use was 25% and efficiency index--1.33. In experimental group the ARVI complicated forms were noted in 3% of the patients and in control group--in 5%. Due to decreased expenses on the treatment of non-complicated and complicated ARVI forms the cost of therapy of one servicemen in the first group was 290.6 rubles, in the second group--323 rubles, in the third group--336 rubles and in the fourth group--368 rubles. The results of investigation have shown the significant advantage of arbidolum therapeutic-and-prophylactic use compared with other variants. Its use permitted to decrease the febrile period, to reduce the manifestation of symptoms of intoxication and affection of upper respiratory tract.