Using personal dosimeters worn during two complete work-shifts, we measured occupational exposure to Extremely Low Frequency-Magnetic Fields (ELF-MF) in 290 workers employed in 56 jobs, representative of the main occupational activities in the area of Modena and Reggio Emilia (Italy). Environmental non-occupational exposure was also monitored. In the whole sample, the mean Time-Weighted Average (TWA) exposure during work resulted 0,9 μT (SD 3,2), while the median was 0,13 μT. Exposure was lower than 1 μT in more than 90% of the workers. In one job only exposure was greater than 1 μT (job-related median TWA); in other 8 exposure was between 1 and 0,4 μT, while about 84% of the jobs presented a median TWA lower than 0,4 μT. A high variability among workers engaged in the same job resulted in various occupational tasks. Non-occupational exposure was lower than 0,4 μT in more than 98% of the examined workers. Our results show a low to moderate occupational exposure to ELF-MF in the greatest part of the workers and working activities. Also the non-occupational exposure resulted low in the large majority of the subjects. The high variability observed among workers engaged in some occupations may represent a problem in exposure evaluation. Personal monitoring is particularly useful in such a situations