The beam spatial structure of mid-infrared laser radiation delivered by hollow glass waveguides was investigated. As laser sources, flashlamp pumped EnYAG, Tm:YAG, and diode pumped Tm:YAG, and Tm:YAP laser systems generating radiation in a free-running regime were designed and constructed. The base of the transfer systems was the cyclic olefin polymer-coated silver hollow glass waveguide having an inner diameter of 700 μm and length up to 1.3 m. The changes of beam spatial structures through the delivery system are presented. For EnYAG laser system the waveguide was investigated for both straight and bent cases, and also the output laser beam stability was observed. The energy transmission characteristics were measured for all systems.