| خلاصه مقاله | Background and Objective: Various equipments that are source of electromagnetic field, and are used with wide- ranging in everyday life, can be damaging. Powerlines and household electrical appliances (TV, Computer, and hairdryer) emit ELF-MF. As the exposure of these MF is creasing now days and important effect of MF on memory formation, in this study effects of these fields on memory consolidation and retrieval was examed. Materials and Methods: 90 male wistar rats were divided into nine groups. Control group was trained in shuttle box (passive avoidance box) and tested 24 hrs later. Sham group was put in turn off MF immediately after training for 4 hrs and tested after 24 hrs. Four test groups of memory consolidation after training were exposed on MF for 1,4,6,8 hrs respectively and tested afler 24 hrs. 3 test groups of memory retrieval after testing, were exposed on MF (4 hrs) for 3, 4, 5 days respectively and were tested again 24 hrs after the last exposure. In all of groups, the time of entrance from light to dark area was measured in shuttle box as' retention latency. Findings: In 4 test groups of memory consolidation. between first group that is exposed on MF for I hr (485-76s), and control group (58317) difference wasn't significant (P0.05) while in other groups that were exposed on MF for 4,6,8 hrs (303+17, 294+87, 191+72) difference was significant (P0.05). Between sham group (541258) and test group that was exposed on MF for 4 hrs (303+ 17) difference was significant (P |