When 366 dispensary patients with respiratory diseases were examined in Moscow during the period December 1969--May 1971, 49 strains of rhinoviruses were isolated out of which 21 strains were identified as type 48. Using Eagle\'s medium with a single set of amino acids and vitamins for isolation rhinoviruses were isolated in 4.7% of cases, empdoying Eagle\'s medium with a double set of amino acids and vitamins in 16% of cases. Virus isolation experiments were carried out in HeLa-Bristol cell cultures and diploid strain of skin-muscle cells KM-13-70 in the presence of 30 mM MgCl2 and 2% aminopeptide. The isolation rate of rhinoviruses in both the cell cultures was approximately similar. The average duration of time for isolation of rhinoviruses in diploid cells was 13.4 days, in HeLa-Bristol cells 15 days. All rhinovirus strains were isolated within 3 passages. In addition to rhinoviruses, from the same group of patients 25 Coxsackie A-21 strains, 12 adenovirus strains and 2 herpesvirus strains were isolated using Eagle\'s medium with double set of amino acids and vitamins.