The main assumption of this research was to check and verify the behaviour of a few EPN (European Permanent Network) stations on both sides of the Teisseyre-Tornquist zone (T-T zone), which is located on Polish territory and crosses Poland almost in half. The selected EPN stations’ time series were a subject of frequency and phase analysis. The main purpose of the research was to verify if there is any correspondence between stations located on one and on the other side of the T-T zone. The idea was also to check if any geological phenomena occurs on examined stations through the behaviour of the stations. The chosen period of research was between 2003 and 2008. The stations’ selection is not coincidental, VLNS, LAMA, BOGO, JOZE, BOR1 and WROC were chosen, because they had the longest and constant solutions provided by EPN. Using wavelets as a tool for analysis, the authors detected biases in time series on chosen EPN stations (near T-T zone). Applying multiresolution wavelet analyses on different stations in the component Up the frequency bands were achieved. The authors decided to analyze the low-frequency bias (wavelet approximation band). The reason of using this tool was to analyze the frequencies and also to compare the frequency phase, in order to have more complex analyses of physical phenomena of the T-T zone in Poland., Pawel Kaminski, Mariusz Figurski, Karolina Szafranek and Krzysztof Kroszczyński., and Obsahuje bibliografii