Actuality: Urological problems are common in the elderly, and the care of patients aged 65 and older forms a significant part of the practice of many urologists. However, this has also created unique challenges for the development of the field of geriatric urology as a specific specialization. In this regard, we conducted a study to identify markers of differentiation of the most common age-associated diseases, such as benign prostatic hyperplasia and malignant prostate cancer, as well as to identify the age most vulnerable in terms of such diseases. Objective: To study the comparative assessment of indicators in elderly patients with benign prostatic hyperplasia and malignant prostate cancer. Materials and methods: To carry out a comparative assessment of laboratory parameters in elderly patients with benign prostatic hyperplasia and malignant oncological formation of the prostate gland, we evaluated the parameters on an automatic biochemical analyzer Dirui CS-1600, a floor model with random access. An assessment of indicators with statistical processing was also carried out. Results: A combination of hemoglobin values below 120 g/l, creatinine below 70 mmol/L, urea above 6.5 mmol/L may be relative markers of differentiation between benign prostatic hyperplasia and malignant prostate cancer, since the percentage of changes is low. The most significant indicator was the PHI index (prostate health index), which was 51.2% higher than in patients with benign prostatic hyperplasia. Conclusions: In the age group of 70-79 years, the diagnosis of prostate malignancy was most difficult, which requires additional development of a differentiation marker at this stage of life. An increase in the volume of prostate tissue reduces the diagnostic value of determining the absolute concentration of oRSA in blood plasma. Piecewise linear regression analysis revealed that the critical value in this sense is the volume of prostate tissue over 41 cm3: R=0.932 p=0.067, the value of the explained variance is 85.1%.