This paper presents the use of a GTEM in an interlaboratory comparison. The GTEM cell is Gigahertz Transverse Electromagnetic waveguide, which has its operation described in IEC 61000-4-20. The comparison program of radiated emission was lead in accordance with CISPR 22, standard that normalizes limits and methods of measurement of radio disturbance for information technology equipment. The performance of the GTEM Cell was compared with other measurements using full anechoic rooms (FAR), semi-anechoic chambers (SAC) and open area test site (OATS)