This presentation reviews the development and research rationale for a Return-on-Investment (ROI) calculator tool for a web-based application available to the public and targeted to employers. The calculator is designed to estimate the population prevalence, the cost burden to employers for three common health conditions – cardiovascular problems, depression, and alcohol abuse – at a specific organization. The calculator is called the IntelliPrev™ Return on Investment Tool and is available online at www.intellipev.com. When one uses the tool, there are two sections: The Input section and the Results section. The “Input” section asks five inputs about the workplace (number of employees, type of organization, location, industry, and the percent of full-time workers). It also asks about workplace health and productivity climate and estimated levels of program participation. These nine inputs are also used to make a key or grand estimate of overall health and productivity. The tool estimates the “disease burden” associated with the three health conditions and adjusts for the co-occurrence or overlap across the health conditions. The tool estimates the number of employees affected and also the associated costs in three areas: Health care, work productivity and employee absenteeism. The tool also estimates total disease burden in dollars for the company. The second output is an estimated savings from improved outcomes. This second set of estimates is the reduction in disease burden that can be reasonably expected to occur when investing in prevention programs. The third output combines the savings with the disease burden to yield the ROI dollar figure. This figure assumes an employer investment at so much per employee/per year for participating in a program compared to the estimated savings. The process for developing this tool was grounded in personal experience and a comprehensive review of the research literature. The components of the model were selected based on research evidence in the mental health and worksite wellness fields. The economics and human resources literature was also reviewed for logical models and dollar default inputs for the dollar value of workplace outcomes. A unique component of the ROI tool is that both the prevalence rate for these three health problems and the level of improvement to each from interventions are adjusted automatically by the level of overall work climate and organizational health.