Characterization of the acoustic field of a shock wave lithotripter is important for determining the performance of the device. In this study, we compare the performance of a newly developed Light Spot Hydrophone (LSHD) with the current standard, i.e., the Fiber Optic Probe Hydrophone (FOPH). An electromagnetic (EM) shock wave lithotripter was selected and each hydrophone was used to map the acoustic field of the lithotripter. The peak positive pressure P+, peak negative pressure P-, pulse duration, and effective acoustic energy were calculated using the collected data. Both the LSHD and the FOPH have similar measurement characteristics. They both provide excellent P+ measurement accuracy and response. Although the LSHD was found to provide more repeatable P- pressure measurements, both devices provide excellent pressure measurement of lithotripter shock fields. © 2007 American Institute of Physics.