Introduction: The application of ultrasound in the brain evaluation of the neonate allows the measurement of brain structures. Objective: To obtain the sizes of the third ventricle and the ventricular index of Levene in a group of Ecuadorian neonates without neurological alterations. To establish normal ranges that can be used in the daily work of the neonatology service. Methods: A group of neonates without neurological alterations was studied. Through the anterior fontanelle, the Levene index was determined. The third ventricle’s diameter was seized through the temporal cranial window. Results: Sixty-six patients of 37 weeks’ gestational age at birth (range 27-42 weeks), predominantly male and an average weight at birth of 2554 grams, were included. The third ventricle’s mean diameter was 1.5 mm (range: 0.5 mm – 3.8 mm). The average Lindergaard index was 12.7 mm (8.2-27 mm). Both, the diameter of the third ventricle and the ventricular index were affected by the birth weight of newborns. Regarding the moment of delivery, there was no significant difference in ventricular size. Conclusions: Compared with the results of other series, our study offers different parameters.