Advantageous properties of plastic materials, low investment costs for a production, cheap and productive processing method were given the rapid development of plastic materials. In this time injection molding technology is the most using technology for processing plastics in our country. Quality of the plastics processing depends mainly on the quality of material and preparing it for production. The first step in the processing of plastic by injection molding is dosing of granulations from hopper of injection machine unit. Task of this contribution is to theoretically describe a pneumatic method for transport of granulations in injection molding machine.