Advances in high frequency electronics, photonics and materials science as well as variety of possible applications enabled rapid development of terahertz technology in last decade. Research on reliable sources and detectors of electromagnetic waves in the terahertz range allows their application in various fields of science and technology ranging from medicine and biotechnology to pharmaceutical, chemical and material sciences. In this paper selected applications in nondestructive testing are shown, especially glass and basalt fiber-reinforced composites inspection as well as terahertz tomography.