The aim of the present study was to observe how the exposition of the pregnant rats to the electromagnetic field (EMF), with frequency of 60 Hz, magnetic field of 3 microT for 2 h per day and/or using the so-called regional basic diet (RBD) influenced the reflex maturation in their offspring. Four groups were formed: Group A (casein), B (casein and EMF), C (RBD) and D (RBD and EMF). The diet manipulation occurred during the pregnancy. The reflexes--assessed daily between 12:00 and 14:00--were: palm grasp (PG), righting reflex (RR), cliff avoidance (CA), vibrissae placing (VP), negative geotaxis (NG), auditory startle (AS) and free-fall righting (FFR). The association between EMF and deficient diet caused a delay in all reflexes when compared with Group A. When the diets were compared with both groups exposed to EMF, the delay occurred in the RR, VP, NG and CA in Group D. In the Groups C and A, the delay was observed in RR, CA, VP, NG, AS and PG. In relation to the EMF, Group B differed from Group A in CA, AS, FFR and PG and Group D differed from C in the PG. In conclusion, all the reflexes studied in this research were delayed by the association of the EMF with undernutrition during pregnancy.