Within the framework of the study laboratory investigations and practical measurements at the RTU laboratory were conducted. The study assesses natural losses of products, taking into account the product viscosity as well as the vapor pressure depending on the temperature. The study also included assessing natural product losses in several enterprises during receiving, handling, storing and transporting the products, taking into account the product volumes being handled, as well as the existing technological resources available in the field of customs. The report summarizes experience of other countries, including a number of the EU Member States, in dealing with natural losses of petroleum products, alcoholic beverages and alcohol, and application of standard rates for losses in customs. The study concludes that customs legislation regarding losses of petroleum products should be specified by determining the level of natural losses, measurement errors, as well as their application. The authors of the study suggest that according to the regulations in the field of customs, indicative levels of natural losses could be determined. Indicative levels can be determined taking into account the volume of products being handled in terminals (including pipeline operators) during a specified period of time (e.g. monthly). However, it would not apply to the theft and related cases.