The business of transporting hazardous materials is extremely regulated in the United States, as well as internationally. Familiarity with the regulations set by the Department of Transportation (DOT) concerning this activity is of great concern to Environmental Health and Safety (EHS) and compliance attorneys; however, all attorneys, especially those in-house, should have some basic knowledge of the DOT regulatory structure. Here, the author provides a summary of DOT and hazmat rules, the scope of materials covered and key issues for the compliance and enforcement of these rules.