<div class="htmlview paragraph">A new and meaningful test method for evaluating the performance of lubricating oil filters has been developed under the sponsorship of the U.S. Army MERDC. The test procedure is based upon the multi-pass method previously formulated for hydraulic fluid power filters, which has since been accepted on both national and international levels. The multi-pass procedure assesses only the particle separation characteristics of a filter and isolates all other factors which could influence the results. The development effort which resulted in this new lube oil filter test method required an international opinion survey, industrial advisory meetings, and an extensive testing program. Details of the method are given in this paper along with repeatability and discriminatory test results.</div>