The success of extra-uterine adaptation depends on proper pulmonary function. It is aimed to characterize the pulmonary parenchyma of canine fetuses during the last week of pregnancy by quantitative analysis of B-mode images. Fifteen healthy, pregnant bitches were used, 2.5±1.21 years, 7.03±3.64 kg of varied breeds. From the 56th day of gestation until parturition (time 0), ultrasonography was performed daily, every 12 hours, with the ACUSON S2000/SIEMENS equipment. Echogenicity, echotexture and quantitative analysis were evaluated by images obtained from -96 to 0 hours. A significance level of 5% was used. The qualitative evaluation fetal lung presented homogeneous and hyperechoic echotexture in relation to hepatic tissue. For quantitative evaluation, the software Image-Pro Plus was employed for calculating numerical average pixel values (NPV; echotextural data), pixel heterogeneity (NPV standard deviation), and minimum and maximum pixel values. 73±9% of lung tissues were subjected to echotextural analysis. The NPV average values as well as the minimum and maximum values decreased significantly (p=0.04) from 96 to 24 hours prior to parturition and subsequently increased (p=0.02, r=0.57). For the pixel heterogeneity, there was no significant difference (p≥0.16). Fetal lung ultrasound evaluation can be performed and applied as a noninvasive method. These results are important not only for novelty, but can be used as standard values for comparison with other tissues, adding information in the assessment of fetal maturity in small animals.