Objectives This study characterized personal exposures of Canadian children to 60-Hz magnetic and electric fields and explained the variability. Methods Altogether 382 Canadian children up to 15 years of age wore meters recording 60-Hz electric and magnetic fields over 2 days. Meter location was recorded. Thereafter, meters recorded fields in the center of the children's bedrooms for 24 h. Personal exposures were calculated for home, school or day care, outside the home, bedroom at night, and all categories combined (total). Results The arithmetic mean (AM) was 0.121 mT [geometric mean (GM): 0.085 mT), range 0.01-0.8 mT] for total magnetic fields. Fifteen percent of the total exposures exceeded 0.2 mT. The AM of the total electric fields was 14.4 (GM 12.3, range 0.82-64.7) V/m. By location category, the highest and lowest magnetic fields occurred at home during the day (0.142 mT) and during the night (0.112 mT), respectively. Measurements during sleep provided the highest correlation with total magnetic field exposure. Province of measurement explained 14.7% of the variation in the logarithms of total magnetic fields, and season accounted for an additional 1.5%. Electric heating, air conditioning, and housing type appeared to be useful predictors of magnetic field exposures. Conclusions In identifying differences in children's magnetic field exposures between provinces, measurements at night provided the best surrogate for predicting total magnetic field exposure, followed by at-home exposure and 24-h bedroom measurements. Electrical heating and air conditioning, wiring type, and type of housing appear to be promising indicators of magnetic field levels.