Abstract The objective of this study was histological structure of lungs and liver of lizards. The septal air sacs inside the lizard's lungs are much larger than the alveoli of mammals and the air ducts of birds. Despite the large volume created by the septa in the lungs of lizards, the surface area in contact with air is much less than that of birds and mammals. Muscles on the front side of the lungs locate in the transverse direction of the lung, and due to their constriction, the entrance to the air sacs located in front is narrowed. But the direction of the smooth muscles in the middle part of the lungs is along the length of the partitions, and due to their constriction, the volume of the air sacs decreases. İn the experiments carried out by us, the main part of gas exchange occurs at the front part of the lungs, and air collects at the back part of the lungs. Gas exchange in the posterior sections of the lungs is very weak. Inside the lungs of geckos, there are tubes similar to the air ducts of birds. In lizards exposed to stress, most of the blood is retained in various organs (lung, liver) and the amount of circulating blood decreases sharply. When we observe the livers of lizards by stationaries, the diameter of sinusoids is determined to decrease as the height above sea level increases, but the number of sinusoids per unit area increases.