A holographic particle image velocimeter system has been developed for the study of three-dimensional turbulent velocity fields in volumetric domains. The system employs a unique phase conjugate reconstruction optical design which yields three-dimensional particle images whose resolution, signal-to noise-ratio and accuracy are comparable to hose of high-quality two-dimensional photographic PIV images. This makes possible velocity measurements with accuracy an spatial resolution similar to current two-dimensional PIV. The system also employs a 640 Mflop parallel processing computer with software optimized for efficient PIV interrogation, validation and post-processing. The speed of the interrogation system makes the analysis of volumetric PIV domains feasible. Measurement in turbulent flow are presented.