This paper describes a bilateral comparison between two national metrology institutes, National Metrology Institute of Turkey (TUBITAK UME) and National Measurement and Calibration Center at Saudi Standards, Metrology and Quality Organization of the Kingdom of Saudi Arabia (SASO NMCC). The aim of the comparison is to check the newly installed SASO NMCC radio frequency and microwave laboratory infrastructure and assess compatibility between two institutes. Measured quantity of the comparison is transmission coefficient of fixed attenuators. The comparison was carried out in three months with 3 dB, 6 dB, 10 dB, 20 dB and 30 dB fixed attenuators. Measurements were performed using commercial Vector Network Analyzer in controlled environmental conditions. Two laboratories were used same measurement technique called as short, open, load and through. The analysis of the results provides good agreement between TUBITAK UME and SASO NMCC as a conclusion.