The aim of this study is to evaluate diagnostic accuracy of perineal ultrasound versus cystography in patients affected by urinary incontinence (UI). 40 patients affected by UI were evaluated by voiding cystography and by perineal ultrasound through sagittal scans. Bladder floor related to public simphysis, urethro-vesical angle, bladder neck dilatation after an increase of abdominal pressure with or without urine leakage, were checked. The comparison with urinary cystography gave similar results. In our experience perineal ultrasound study of pelvic floor showed, in the evaluation of urinary incontinence, the same accuracy of the urinary cystography. Ultrasound study allows a good visualization of the anatomic structures of the pelvic floor and of the lower urinary tract and a good evaluation of the tissues; it also offers easy performance, low cost, less invasivity and a better compliance.