The study of the animal body and its morphoarchitectonics is a priority area for the successful development of animal husbandry. The purpose of the study is to establish the macroscopic structure of the lungs and provide an organometric assessment of their morphological structures in domestic sexually mature animals. The study used 30 clinically healthy individuals of 6 animal species belonging to the class Mammalia – Mammals. According to the results of the morphometry analysis of absolute and relative lung values in domestic mammals and their right and left lobes, a pronounced asymmetry was established, the coefficient of which corresponded to: in rabbits – 1:1.30, in dogs – 1:1.33, in sheep – 1:1.37, in pigs – 1:1.34, in cattle – 1:1.37, in horses – 1:1.2. For morphological assessment of typical lung features characteristic of a particular animal species, a morphological scale of marker features of the organ is proposed. According to the results of the study, it is proposed to classify the lungs of domestic mammals, considering the structure and shape, into 4 types: 1st – expanded-shortened (lung development index (LDI) = 85– 100%); 2nd –intermediate (LDI = 101–120%); 3rd – moderately elongated (LDI = 121–130%); 4th – elongated (LDI = 131–140%). Based on a detailed analysis of organometric studies, a scale for assessing marker features of the lung is proposed – in rabbits (LDI = 90 ± 1.89%) assigned to the extended-shortened type, in cattle (LDI=117±2.21%) and sheep (LDI=114±2.08%) – intermediate type, in horses (LDI = 127 ± 2.74%) – moderately elongated type, in pigs (LDI = 136 ± 3.01%) and dogs (LDI = 137 ± 2.84%) – elongated type. The obtained results of morphological studies of the lungs of the representatives of the mammalian class are of practical importance in biology and veterinary medicine since they are marker signs of their morphofunctional state and criteria for pathomorphological diagnosis of respiratory diseases