The effects of protein energy deprivation (PED) on trigeminal ganglion sectional area, neuronal density, number of neurons/section, neuronal body area and neuronal nucleus area were evaluated. The protein deprivation prenatally and for 21 days postnatally leads to reduce body weights (40% of control weights) and an increase in the number of neurons/ section (35% more than control). Most neuron perikarya were within 400-600 μm2 (53,7%) in protein-deprived animals and 600-900 μm2 (48,2%) in the control group. Rows of neuronal bodies were separated by bundles of nerve and collagen fibers in both groups. Ganglionic neurons from both groups contained cytoplasmic Nissl’s corpuscles and spherical nuclei with eccentric and large nucleoli. The elongated nuclei of the fibrocytes revealed the main axis oriented parallel to the bundles nerve fibers. By scanning electron microscopy, the structure of the ganglion from both groups was found to be similar.