Interlaboratory comparisons (ILC) are an important element of quality systems of certified testing laboratories. It is the policy of the majority of certifying institutions to participate in ILC programs concerning research laboratories. ILC programs are technical initiatives. An analysis of the ILC results allows for taking decisive actions-proficiency testing. There are many types of ILC. However, in EMF measurements, the result comparison programs are usually applied. All program participants measure the same EMF source, usually the one that is normally exploited. The authors present the results and analysis of interlaboratory comparisons performed by certified laboratories. Comparisons presented in the paper were performed in the vicinity of the GSM base station.