In a retrospective study four questions concerning urodynamics and lower urinary tract symptoms (LUTS) were answered: Do obstructive symptoms correlate with bladder outlet obstruction? Does the symptom urgency correlate with bladder instability? What is the value of a free uroflow study in men with LUTS? Should all men with LUTS have pressure-flow studies before surgery? The authors state that urodynamic investigation is very important before surgery in patients with LUTS.