Ultrasonography is an important technique in the evaluation of maternal fetal viability in dogs. Recently, elastography has been included in veterinary obstetrics, with promising results. Considering the importance of the techniques, the objective of this study was to evaluate, in the last week of pregnancy of bitches, fetal lung tissue through ultrasound B-mode and elastography ARFI (Acoustic Radiation Force Impulse). Fifteen clinically healthy, pregnant bitches were selected with 7.03±3.64 kg and 1.21±2.5 years, of varied breeds. From the 56th day of pregnancy until parturition (time 0), transabdominal ultrasonography was performed daily, every 12 hours, using the equipment ACUSON S2000/SIEMENS and specific software appliance. The images obtained from -96 to 0 hours were subjected for analyses and checked the sonographic findings, shear rate and its stiffness characteristic. The experimental design was completely randomized and used a 5% significance level. The animals did not have clinical and obstetric changes during pregnancy and parturition. Lung tissue was hyperechoic and homogeneous to sonographic study. Qualitative elastography lung parenchyma of canine fetuses did not appear deformable, being homogeneous, medium gray to light coloring. The average shear speed was (p=0.69 m/s), (CI=0.84±0.11 m/s), and the speeds were statistically similar in all experimental time moments. The ultrasound and elastography examinations of fetal lung can easily be performed during the last week of pregnancy and can be applied as non-invasive methods of monitoring the perinatal development of this organ.