Over the recent years some countries have introduced norms, regulations or recommendations limiting the value of few A/m permissible levels of the 50 Hz magnetic field (MF) in the environment. This results from the studies indicating a number of biological effects on living organisms exposed to magnetic fields with levels similar to those produced by high voltage overhead power lines. The main objective of these restrictions was to protect human health from the effects of MF produced by high voltage overhead transmission lines. The changed permissible level of MF intensity to the level now binding in different countries will have great economic and financial impact. The greatest impact will be observed in the already established residential areas, which require that the levels of magnetic field from existing overhead lines be lowered. The effects of more strict regulations on the protection against the effects of the 50 Hz magnetic field, reducing the levels to values lower than 0.25 A/m, can be grouped into three categories: technical effects, space and landscape implications and financial impact. The lowering of MF maximum acceptable level will require changes in the structure of new power lines and modifications in the existing grid. Unfortunately, the replacing of overhead power lines with cables is not possible on account of too high costs. The extension of the area, in which construction of dwelling houses will not be possible, can turn out to be the only solution. Med Pr 2009;60(1):51-57