The intention of this analysis is mapping variability of the NAIRU because of different methods and application methods on data two different countries. The author aims at detection and analysing in stable condition with structural shifts, which lead to changes in development of the NAIRU in researched countries. On the end of the paper she uses experience to prediction of development of the NAIRU in short future. In article some steps are suggested, which should increase applicability of the concept NAIRU for discussion macroeconomic policies. For the estimation of the NAIRU development, the slope and the shift of the Phillips curve, she applied the system of the methods which are commonly used at the international level. The figure of NAIRU can be investigated as a dependent variable during the research time period. Main factors causing the greatest changes of NAIRU or its fluctuations are apart from the inflation expectations themselves also: import prices, exchange rate, prices of oil and indirect taxes.