Sexually transmitted diseases (STD) may be caused both by one and several agents in one patient. Treatment of combined infections presents certain difficulties, since pharmaceuticals or treatment settings toward some STD agents may be ineffective or insufficiently effective toward other agents. Diagnostics plays an important role in the treatment of combined infections. The diagnostic methods based on the multiplex polymerase chain reaction (PCR) provide the possibility to identify with high diagnostic sensitivity and specificity the spectrum of the main agents, as well as conditions of combined infections. This allows selecting the most effective tactics for treatment of patients. Aim. The aim of the study was to evaluate the proportion of mixed infections and variants of their combinations in patients seeking dermatovenereological help as well as to propose treatment settings based on the existing treatment protocols for the gonococcal, urogenital chlamydia, and trichomonad infections and the infection caused by Mycoplasma genitalium. Material and methods. The study was conducted in patients who applied for medical care to different branches of the Moscow Research and Practical Center for Dermatovenereology and Cosmetology. The infection agents were identified with the PCR methods and the transcription amplification reaction, nucleic acids sequence based amplification (NASBA). A kit of reactants AmpliSens Neisseria gonorrhoeae/Chlamydia trachomatis/Mycoplasma genitalium/Trichomonas vaginalis – MULTIPRIME-FL was used for PCR, and kits of reactants AmpliSens Neisseria gonorrhoeae– RIBOTEST, AmpliSens Chlamydia trachomatis–RIBOTEST, AmpliSens Trichomonas vaginalis– RIBOTEST and AmpliSens Mycoplasma genitalium– RIBOTEST (Central Epidemiology Research Institute, Russia) was used for RNA identification by NASBA. Results. 1676 (68.3%) males and 779 (31.7%) females were examined. In total, 246 cases of infections caused by N. gonorrhoeae, C. trachomatis, M. genitalium, and T. vaginalis were identified in males and 107 in females. The number of infected males was 230 (13.7%), of whom 216 (94%) were diagnosed with a mono infection caused by different STD agents, and 14 (6%) were detected with mixed infections. The number of infected females was 91 (11.7%), of whom the number of patients with mono- and mixed infections was 79 (87.8%) and 12 (13.2%), respectively. The most common variants of mixed infections were the following: N. gonorrhoeae + C. trachomatis (n=8), C. trachomatis + M. genitalium (n=5), and T. vaginalis + C. trachomatis (n=7). Based on the existing domestic and European regimens of treatment of mono-infections as well as on the data of the literature on the efficacy of treating mixed infections with different pharmaceuticals, treatment settings were proposed for therapy of co-infections caused by several STD agents. Conclusion. Multiplex PCR enables, within a single analysis, identification of DNA of one of the four STD agents with high diagnostic sensitivity and specificity, as well as cases of their simultaneous presence in a sample. This approach allows selection of the most effective tactics for patient treatment. Based on the analysis of the data on the incidence of different combinations of mixed infections and the literature data on the methods effective for treatment of certain mixed infections (allowing for the specific responses of microbes to pharmaceuticals), a variant of settings for treatment of co-infections was proposed. This variant will allow the development of treatment tactics simultaneously effective against several types of agents.