We performed open multicentral randomized cohort study in 72 males. Maximum urine flow rate Qmax, average urine flow rate Qave, and also time of urination were defined in all the patients. Qmax in standing position in males was on average 18.1 ± 6.2 ml/s (from 6 to 53 ml/s); Qave - 10.2 ± 2.7 ml/s (the range was from 2.7 to 29.6 ml/s). Urination time in standing position varied from 11 to 120 s (on average 30.5 s). Qmax in sitting position was 17.3 ± 3.5 ml/s (5.4-48.0 ml/s), and Qave was 10.6 ± 2.9 ml/s (2.7-30.5 ml/s). Urination time in sitting position varied from 10 to 109 s (on average 28.7 s). Qmax in sitting position increased by ≥ 1 ml/s in 34.7% of males, Qave increased in 40.3%. Urination quality depends on the number of causes that is why uroflowmetry indices are unstable. Taking into account that maximal and average speed of urine flow in every third male is higher in sitting position we recommend to carry out uroflowmetry in different positions for grounded references on urinary bladder voiding for a specific patient.