In many industrial processes where raw materials are required in bulk, pressure discharge trucks (usually referred to as PD trucks) are commonly used to transport them from the supplier's warehouse or mine to the processing plant or final client. As the name implies, pressure discharge trucks unload their contents by means of a pneumatic conveying system and transport it through a pipeline into a storage silo. This type of material handling system does not employ bags or containers to transport the materials, it is enclosed and easy to operate, and hence, it is less expensive overall when large quantities of materials are to be transported in bulk on a regular basis. In this article, attention is centered on the design and operation of PD trucks, from a pneumatic conveying viewpoint, including a description of several problems encountered in the field. Examples of different applications and bulk materials are also presented.