Abstract: In this study we explore the origin of the high stability of the Lofoten vortex, persistently observed in the central part of the Lofoten Basin of the Norwegian Sea. It is shown that the higher steepness of the southwestern bottom slopes and a small inclination of the bottom topography towards the region where the Norwegian Current splits into two branches increase the dynamic stability of the Lofoten vortex. The observed minor variations of bottom topography of the basin form the area with the small gradients of the background potential vorticity. When residing in this area, the Lofoten vortex can retain 60 to 90% of the core volume over two years, even without gaining energy from external sources. When the vortex deviates from its mean position in the center of the basin, or when the external conditions deviate from their characteristic values for the Lofoten basin, the rate of the Lofoten vortex deformation and decay typically increases. Thus, the topography of the Lofoten Basin together with the characteristics of the Norwegian Current in the study region form almost optimal conditions for the permanence of an anticyclonic vortex in the center of the basin.