The Navy diesel fuel specification (MIL-F-16884H) controls filterable materials (dust, dirt, organic sediment, etc.) by ASTM Method for Water and Sediment in Distillate Fuels by Centrifuge (D 2709-82) with a limit set at 0.01 volume %. If an assumption is made that organic fuel-derived sediment/microparticulates have an average density close to 1.7 times that of diesel fuel (having a density of approximately 0.85 g/mL), then 0.01 volume % sediment in fuel is equivalent to 0.017 mass %. Micro-particulate analysis by ASTM Methods for Particulate Contaminant in Aviation Turbine Fuels [D 2276-73 (1978)] would potentially then measure up to 145 mg/L of filterable particulate. This amount of particulate material is intolerable and would rapidly plug filter separators and diesel/turbine engine fuel filters. Currently, Navy field guidance is for filterable fuel insolubles not to exceed 15 mg/L by ASTM D 2276 for acceptable filter separator performance. A portable diesel fuel microparticulate analyzer utilizing glass fiber fuel filters and light transmittance has been developed for testing marine diesel fuel aboard ships of the U.S. Navy. This analyzer (tester) is one of four different testers in a portable diesel fuel test kit developed for Navy use aboard ship or ashore. The test kit includes testers for color, flash point, free water, and microparticulates. This paper describes the design, development, and demonstration of this test kit with major emphasis being placed on the design and use of the filterable microparticulate tester. Comparison of this tester to other similar devices is also provided.