The aim of the study was to determine, using perineal ultrasound, the physiological range for urethral mobility in normal women. Sixty healthy women were enrolled. The ultrasound parameters obtained with a perineal "static" and "dynamic" evaluation method were: pubic-urethral distance and inclination angle of the urethral axis. We propose a physiological range of pubic-urethral distance under stress in young women between 10 and 15 mm, the inclination angle of the urethral axis is between 60 and 100 degrees . In peri-post-menopause women we establish a non-rigid range of mobility in relation to age and parity: between 15 and 18 mm for the pubis-urethra distance and 80 degrees and 120 degrees for the angle of the urethral axis. Defining a range of normality for urethral mobility through ultrasound is useful for further studying therapeutic choices and help to identify the surgical correction and post-operative follow-up.