Over the years physiologists have proposed models that would explain the function of the ureter. However, these models being qualitative were unable to predict the observed variations in the ureteral parameters and some have even been contradicted by modem physiological observations. Recently, several articles on peristaltic transport have appeared in the engineering literature. Some of these articles introduced models suitable for ureteral peristalsis. These models are reviewed and evaliiated on the basis of physiological observations of which the urometrogram plays an important part, it being the major research tool in urology. Then a fluid mechanical model capable of producing such urometrograms is presented. This model is instrumental in explaining other physiological observations such as the time lag between the start of the ureteral contraction and the pressure pulse, the lack of correlation between parameters in many experiments, retrograde migration of bacteria, the reason for the ineffectiveness of the hydro-ureter, the trapping mechanism for a fluid bolus, etc. In addition, it is shown that a catheter inserted in the ureter has no effect on the shape and physiological meaning of the urometrogram,