Objective — to investigate the efficiency and safety of course therapy with low-dose sildenafil in males with low- and intermediate-risk coronary heart disease (CHD) (according to the Princeton Consensus) and erectile dysfunction (ED). Subjects and methods. The open-label, randomized, comparative clinical trial enrolled 50 males aged 40—69 years with low- and intermediate-risk stable CHD (according to the Princeton Consensus) and ED. The males with CHD and ED were randomized to two groups matched for main indicators. Along with previous basic treatment for CHD, a study group (n=27) received sildenafil at a dose of 25 mg thrice weekly. A month later, the dose of the drug was escalated to 50 mg. A control group (n=23) had only previous basic treatment for CHD. The duration of therapy and follow-up was 3 months. Changes in erectile function, the symptoms of urination, the intensity of chronic stress, hemodynamic, anthropometric, and ECG parameters were evaluated before and after the investigation. Results. After completion of sildenafil course treatment for ED, the data available in the international index of erectile function (ICEF) questionnaire indicated that erectile function improved almost twofold, which turned out to be statistically significant as compared with the baseline value and with the control group. During sildenafil therapy, there was a 30% average decline in urination symptoms, as estimated by the International Prostate Symptom Score (IPSS) scale, whereas no changes in the overall total score on the above questionnaire were seen in the control group. The questionnaire survey demonstrated that the level of chronic stress decreased by one third in the study group. The changes in stress intensity were not significant in the control group. Resting ECG analysis during therapy with sildenafil at a dose of 50 mg/day did not reveal negative changes in the rate of arrhythmia and conduction disturbances and in the measurements of myocardial blood supply. Conclusion. Low-dose phosphodiesterase type 5 inhibitors as course therapy can be considered as ED treatment in patients with low- and intermediate-risk CHD (according to the Princeton consensus) as part of combination therapy.