Diesel particulate matter (dpm) is a normal byproduct of diesel fuel combustion. It is composed mainly of submicrometer, insoluble, carbonaceous soot agglomerates, and adsorbed or condensed soluble organic compounds. Dpm is almost entirely respirable in size; therefore, it is regulated under the respirable coal mine dust standard. Tests conducted by the U.S. Bureau of Mines have shown that an engine in good mechanical condition can emit up to 300 mg/scm of dpm, and those in need of maintenance can emit much higher concentrations. To ensure that dpm is not a major contributor to the respirable dust in mines, emissions should be reduced to the lowest possible levels. An industrial hygiene strategy aimed at reducing dpm levels in mines should include a combination of work practice modifications, emission controls, and regular monitoring of dpm levels. Work practices that should be emphasized include engine and fuel selection, engine maintenance, operator habits, and ventilation. Emission controls such as fuel additives, catalytic converters, water scrubbers, and diesel particulate filters should be considered. In some cases the use of emission controls may decrease the levels of some contaminants, while at the same time incresing the levels of others; thus they must be carefully evaluated before being selected for in-mine use. The objective of this report is to present information on the work practices and diesel exhaust controls that can be used to reduce dpm emissions now and in the future. A brief discussion of state-of-the-art dpm monitoring methods is included.