THIS CHAPTER INCLUDES THE DETAILS OF DIStillation measurement test methods for petroleum products performed at atmospheric pressure. The test methods covered are ASTM D86-04b “Standard Test Method for Distillation of Petroleum Products at Atmospheric Pressure” [1], D850-03 “Standard Test Method for Distillation of Industrial Aromatic Hydrocarbons and Related Materials” [2], and D1078 “Standard Test Method for Distillation Range of Volatile Organic Liquids” [2]. The salient features of these test methods are discussed in detail to provide information that is essential to a fuller understanding of the test procedure and to allow the practitioners of this measurement to perform the test in a manner assuring conformance to the method. Examples are given for calculations required to illustrate how reported distillation results are obtained, and explanations are provided for details of the test method that may not be obvious to users of the method. A brief discussion of D402-02 “Standard Test Method for Distillation of Cut-Back Asphaltic (Bituminous) Products” [3] will be given at the end of the chapter to complete the discussion on distillation measurements for petroleum products.