ABSTRACT. Silva M.P.S., Ferreira L.T., Santos-Sousa C.A., Gomes M.S., Palhano H.B. & Abidu-Figueiredo M. [Morphology and morphometry of the adrenal glands in cats by ultrasound.] Morfologia e morfometria das glândulas adrenais em gatos através da ultrassonografia. Revista Brasileira de Medicina Veterinária, 38(1):91-98, 2016. Programa de Pós-Graduação em Medicina Veterinária (Patologia e Ciências Clinicas), Universidade Federal Rural do Rio de Janeiro, Campus Seropédica, BR 465 Km 7, Seropédica, RJ 23897-970, Brasil. E-mail: firstname.lastname@example.org The literature that refers to the size of the adrenal glands in cats of different sizes and ages is not yet sufficiently reported. New measurements of the adrenal glands in cats without evidence of adrenal diseases will provide new data about the normal size of these glands, contributing to an earlier and precise imaginologic diagnose of related pathologies. Ultrasonography is the most commonly used method of diagnostic imaging in veterinary medicine to evaluate the adrenals, due to the fact that in most cases, there is no need to sedate the animal, its low cost and its safety. The aim of this study was to perform ultrasonographic measurements of the adrenal glands in cats without evidence of adrenal disease and/or diseases that are proven to change the size of the glands in order to contribute to a reference value in the species. We used 30 mongrel cats, aged from 2 to 18 years, neutered and non-neutered of both sexes. Measurements of adrenal included the length (craniocaudal) and height (dorsoventral) of both poles in longitudinal section. The average length of the left adrenal was 9.88 ± 0.15 mm and the right one was 10.45 ± 0.14 mm. The mean heights of the cranial poles were 3.6 ± 0.5 mm in the left gland and 3.75 ± 0.49 mm in the right one. In respect to the heights of the poles of the adrenal glands, the means were 3.54 ± 0.55 mm on the left and 3.6 ± 0.46 mm on the right. The glands although similar, feature three forms: the most common being the bean shaped, then the oval shaped, and the less frequent, the elongated. The present study indicates that the size of the adrenal glands in mongrel cats, in the selected group did not depend on the weight of the animals, their age, sex, FCMI (feline corporeal mass index), and if they were castrated or not.