The results of evaluating the effectiveness of C. diphtheriae inoculation using different types of dry swabs in studies simulating various conditions of its storage at the preanalytical stage of a laboratory study for diphtheria are presented. A typical toxigenic strain of C. diphtheriae biovar gravis No. 665 was used. A commercial dry, sterile cotton swab probe (Ningbo Greetmed Medical Instruments Co., LTD, China), a commercial dry, sterile swab probe (plastic and viscose) (COPAN, Italy), tufters with a fluffy probe-tampon on a polystyrene applicator, standard (DELTALAB, SL, Spain). The tampons were pooled with a 24-hour bacterial culture of C. diphtheriae, then immediately seeded on Tellurite-containing blood agar and Corynebacagar. Storage conditions were simulated for 3 hours: at room conditions +(20-25)°C, in the refrigerator +(4-8)°C, in a thermostat +(37±1)°C. Optimal storage of C. diphtheriae on all three types of dry swabs at + (4-8) ° C; at +(20-25)° C - growth is observed when seeding from a cotton swab; in a swab with a fleecy probe-tampon, a decrease in the inoculation of C. diphtheriae was noted; when using a viscose swab - a significant loss of C. diphtheriae. At +(37±1)°C, a significant decrease in the inoculation of C. diphtheriae on all three types of tampons was noted, up to the absence of growth when using a viscose tampon. To exclude the loss of C. diphtheriae, it is necessary to observe the conditions for taking and storing biological material at the preanalytical stage of a laboratory study, which will improve the quality of laboratory microbiological studies for diphtheria infection.