Objective: to investigate the efficiency of incorporating Cytoflavin in combination with individual cognitive psychotherapy into palliative care regimens in elderly and senile patients with Stages III—IV rectal or breast cancer. Subjects and methods. Therapy was analyzed in 175 patients aged over 61 years with Stage III—IV rectal or breast cancer. All the patients were treated in accordance with Order No. 187н by the Ministry of Health of Russian Federation and divided into 2 groups: 1) in addition to basic treatment, 70 patients received individual cognitive psychotherapy and Cytoflavin in a dose of 2 tablets twice daily for 25 days; 2) 105 patients who had standard palliative treatment. Treatment efficiency was evaluated from quality of life in patients through interviews using the Russian version of the the European Organization for Research and Treatment in Cancer Quality questionnaire (EORTC QLQ-C30 (Version 3)). Results. The use of Cytoflavin during individual cognitive psychotherapy in combination with palliative care improved quality of life, which manifested as a significant decrease in the indicators of fatigue (p<0.01), pain syndrome (p<0.01), and insomnia (p<0.05), an improvement in appetite (p<0.05), a significant increase in the indicators of the functional scale: physical functions (p<0.01), cognitive function (p<0.05), role-playing and emotional functions (p<0.05), social function (p<0.05), and an improvement in the overall status scale. Conclusion. The findings allow Cytoflavin to be recommended for its incorporation during individual cognitive psychotherapy into palliative care regimens in cancer patients.