Morphological and morphometrical studies of the myenteric plexus of the mouse large intestine were performed using NADH diaphorase and acetylcholinesterase staining. Male albino mice (70-80 days old) were sacrificed after ether anaesthesia and the large intestine was immediately removed and submitted to the staining techniques cited above. Then, the colon was divided into three segments of the same length (first, second and last third) from the proximal to the distal end. The fragments were dissected, the mucosa and submucosa removed, lasting only the tunica muscularis. The membranes were mounted on slides and covered with coverglass for microscopic examination (4x and 10x objectives). At least 10 micrographs of each segment of the intestine were used for the point counting method for evaluation of the surface area of the plexus (4x micrographs). For neuron counts 10x micrographs were used. Nerve cell bodies volume and area were evaluated on 40x micrographs. The results showed: a) the myenteric plexus in the large intestine of the mouse is more dense in the proximal third of the colon than in the distal third; the number of neurons/cm² is significantly less in distal segment of the colon (65767 ± 10341 neurons/cm²) than in the proximal and intermediate segments (93242 ± 9185 neurons/cm² and 85188 ± 5154 neurons/cm², respectively). The mean volumes of the neurons were similar in the different segments of the colon (4549 ± 3493 μm³).