Ultrasonic non-destructive testing (NDT) is one of the main technical means for monitoring of the human environment with its various potentially risky technological systems and engineering constructions. NDT guarantees a safer exploitation of such objects as well and safer life for humans.The intended activity of the infrastructure focuses on the development and application of ultrasonic NDT, diagnostic and measurement techniques. Different materials are investigated at the Ultrasound Institute (UI) of Kaunas University of Technology (KTU) in order to extract information about the physical-mechanical characteristics of the tested objects and their changes. The results make it possible to develop: 1) innovative new ultrasonic NDT measurement methods and systems for testing of composite materials, 2) ultrasonic NDT and monitoring methods of large metallic constructions having non-standard dimensions, based on the application of ultrasonic guided waves (Long-Range Ultrasonics), and 3) special ultrasonic transducers for measurements in extreme conditions like high temperatures, pressures, high levels of radiation, applications in medicine etc.