The PREscore software package has been developed to assist site assessment investigations and Hazard Ranking System (HRS) scoring by generating a Preliminary Ranking Evaluation score and associated documentation. The users manual consists of three parts. Chapter 1, 'Getting Started', introduces you to the software package and takes you through the procedures necessary to install PREscore software on your computer. Chapter 2, 'Tutorial', provides an initial step-by-step 'hands-on' lesson in using PREscore by 'walking' you through a series of screens, entering and editing data. Chapter 3, 'Printing', provides instruction for using PREprint, which performs printing functions on PREscore site files. The manual assumes some familiarity with the IBM PC-type platform. Actual scoring of a site with PREscore requires little, if any, knowledge of the Disk Operating System (DOS).