Abstract.Using the 21 F 01 DISA Mictiograph, the instant urine flow curves of fifty normal males and thirty‐three females (aged from 18 to 35 years) were analysed. A total of 363 micturitions was obtained (146 in the female group, 217 in the male group). Ten parameters were derived from each of the urine flow curves. These parameters were: the voided volume, the micturition time, the average‐flow rate, the flow at 2 s, the maximum flow‐rate, the percentage of difference between the maximum flow rate and the average‐flow rate, the duration until the maximum flow rate, the initial slope of the curve, the slope at the time from micturition initiation of voiding to maximum flow, and the difference between the two slopes. This study demonstrated that the urine flowmeter allowed, even at very low voided volume, a complete interpretation of micturition flow curves, a finding which might be useful in paediatric patients. It was also shown that the flow parameters were significantly more favourable in females than in males, and consequently that better hydrodynamics conditions for micturition exist in women compared