Background: One of the aspects of action of low frequency magnetic field in treated patients to which is payed attention is it’s influence on blood pressure. Because of existing controversies our aim was to investigate the influence of the extremely low frequency magnetic field on blood pressure in patients treated because of spine osteoarthritis. Material and methods: Fifty seven female in mean age of 60±8,6 years were examined who were treated because of spine osteoarthritis. Magnetic field of 5 mT, 20 Hz, rectangular was used for 15 minutes exposure, once daily, together 10 exposures on lumbal segment. There were two groups of patients: group I – 25 patients with hypertension and group II – 32 patients with normal blood pressure. The blood pressure was measured 3 times in each patient: 1st measurement – after 15 minutes rest, just before intervention, 2nd measurement – just after the intervention, 3rd measurement – 15 minutes after intervention, on each intervention day (10 days). Results: Decrease in systolic and diastolic blood pressure was observed just after the intervention, maintained for 15 minutes, as a result of a single intervention as well as of a series of interventions, in patients with hypertension and with normal blood pressure. In addition in patients with hypertension decrease in blood pressure measured before intervention was observed after a series of interventions. Conclusion: Our results confirm hypotensive effect of magnetic field used for the treatment of spine osteoarthritis, lumbal segment.