Increase in bladder stiffness could be associated with various pathophysiologic conditions. We introduce Ultrasound Bladder Vibrometry (UBV), a novel method for rapid and noninvasive measurement of bladder wall viscoelasticity. UBV uses acoustic radiation force to excite mechanical waves in the bladder wall and track the motion using ultrasound pulse-echo techniques. Fourier domain analysis of the tissue motion versus time is used to calculate the phase velocity dispersion (change of phase velocity as a function of frequency). The measured phase velocity dispersion is fit with the antisymmetric Lamb wave model to estimate tissue elasticity and viscosity.