The paper presents an analysis of the possibilities of using a data set of Sentinel-1 (S-1) Interferometric Synthetic Aperture Radar (InSAR) for urban monitoring. The study was conducted in the Olsztyn area, where by using the PSI (Persistent Scatterer InSAR) method the amount of deformation was determined, calculated using a multi-time SAR data series. Displacement values were estimated by reducing error sources related to temporal and geometrical decorrelation and atmospheric phase delay. Based on the defined assumptions, three calculation cases were prepared. This processing is based on the data from more than 648 Sentinel-1A/B images over ascending and descending orbits acquired between October 2014 and August 2018 to determine the value of the Line of Sight (LOS) ground deformation rates. Regular acquisition of SAR images from the Sentinel-1 satellite sensor in an interval of 2 days enabled the detection of more than 1000 PSI points per 1 km2 in the 10 × 10 km2 urban area. The mean LOS velocity of surface change was determined on the basis of four large data sets. and Comparable values were obtained from ascending tracks 29, 102 and descending tracks 51, 124 where mean velocity ranges respectively: A29 from -4.3 to 3.4 mm/yr, A102 from -3.9 to 3.5 mm/yr and D51 from -3.9 to 3.1 mm/yr, D124 from -3.8 to 3.2 mm/yr. Then the results of geometries were combined in pairs to compute the actual vertical motion component. In the presented work, an analysis of the terrain deformation was performed for selected characteristic objects located within the Olsztyn area. In the first case study, a detailed analysis of urban infrastructure facilities was carried out, including buildings and a section of the railway line. The other case study covers an area along the river bank. A large number of observations allowed to accurately determine the deformation model and to produce the history of deformations on the tested area, based on the analysis of time series of interferograms. The paper presents solutions using InSAR data in urban monitoring and shows why this technology is a useful tool for studying measuring urban subsidence. The results are displayed in the form of a deformation map showing the magnitude of the measured movement.