The paper summarizes and reviews the document World Health Criteria 35. The purpose of the Criteria 35 is to provide information for health authorities and regulatory agencies on the possible effects of extremely-low-frequency (ELF) electric and magnetic fields on human health and to give guidance on the assessment of risks from occupational and general population exposures. The Criteria Document includes a review of biological effects on human beings and animals exposed to ELF fields in the frequency range of 0-300 Hz with emphasis on power (50- and 60-Hz) electric fields. Subjects reviewed in the document include the physical characteristics of ELF fields, measurement techniques and dosimetry, levels of exposure from devices in common use, mechanisms of interaction, biological effects in animals and animal tissues, human studies, health risk evaluation, and guidance on the development of protective measures such as regulations and safe-use guidelines.