Numerous electronic devices have been introduced into the operating room. Although little is known about the relationship between exposure to electromagnetic fields (EMF) and health hazards, some authors reported its association with cancer or other diseases. We measured the amount of EMF exposure that an anesthesiologist gets in the operating room. The density of the magnetic field was checked by an extremely low frequency (ELF) field strength measurement system in the 19 operating rooms of our hospital. We measured the magnetic field intensity at a distance of 30 cm, 50 cm, and at the place where the anesthesiologist usually stands from the center of the main monitor. The average exposure quantities of magnetic fields in 19 operating rooms were 2.22 ± 1.13 mG at 30 cm, 1.29 ± 0.84 mG at 50 cm and 1.00 ± 0.78 mG at the anesthesiologist's standing points respectively. Because quantities over 2 or 3 mG were accepted to be high radiation levels of EMF by many reports describing the hazards of EMF, we set 2 mG to be the cutoff value. In some of the 19 operating rooms, the measured EMF density exceeded our cutoff value. Although the health hazards related to EMF exposure are still equivocal, anesthesiologists should consider making an effort to improve their environment and reduce their exposure to EMF.