Aim: To study the effect of extra-corporeal shock wave (ESW) on the penile hemodynamics and histopathology in rats. Methods: Adult male Sprague-Dawley rats were divided at random into 3 groups. ESW application was performed with a Siemens Lithostar With the rats under anesthesia lying prone on the balloon probe. Rats in Group I received a total of 1000 shocks at 18 kV and immediately underwent hemodynamic evaluation performed by direct electrostimulation of the cavernous nerve and measurement of intracavernous pressure (ICP). Rats in Group II received 3 times 1000 shocks at 18 kV at weekly intervals and hemodynamic evaluation was performed 1 month after the last ESW application. Group III served as the control. Histopathological examinations of penile tissues were done on Masson's trichrome and hematoxylin and eosin stained sections. Results: Penile hemodynamic evaluation showed a trend toward a diminished mean maximal ICP, duration of erection, ICP during the plateau phase and maximal ICP/ blood pressure ratio in Group I, although there was no significant significance. The mean latency period in Groups I and II was prolonged. Petechial bleeding within tunical layers and small foci of hemorrhage within the corpora cavernosa were observed in Group I. However, histopathological examination failed to reveal any significant differences between the groups in terms of smooth muscle content, tunical thickness, organization of collagen bundles and elastic fiber-lattice framework. Conclusion: ESW has certain damaging effects on the penis.