The aim of this study was to investigate the effect of weak static magnetic fields on human heart rate variability (HRV). So far, literature has mainly focused on the health effects induced by strong static magnetic fields. HRV is a temporal fluctuation of heart rate, which the literature has shown to be an adequate indicator for assessing the state of the autonomic nervous system. By autonomic nervous system one could also assess in real time if and when the organism falls into stress. In this blind experiment the subjects were exposed to 150 microTesla magnetic field for a few minutes. The heart activity of the subjects (n = 116) was recorded and the dynamics of the HRV frequency components i.e. reaction of the sympathetic and parasympathetic nervous system analyzed by repeated measures analysis of variance (ANOVA). No statistically significant difference (p < 0.05) were found in low frequency (LF), high frequency (HF), total power (TP), HF/TP ratio, LF/HF ratio nor between hear rate (HR) means in between the exposure and pre- or post-control stages of the experiment. However, observations made by the researchers suggest, that a small portion of the population may indeed be affected by slightly elevated static magnetic fields but the screening method needs further elaboration.