The goal of the present study was to evaluate the effect of unilateral ureteral ligation on blood constituents, renal histopathology and ultrasonography in dogs. A total number of 25 apparently healthy adult mongrel dogs belong to Assiut city, Egypt were subjected to study. Animals were divided into 5 equal groups; the left ureter was ligated for 2, 7, 14 and 21 days in group I, II, III and IV, respectively. Group V represented the control group. The animals of the groups I-IV were euthanized on days 2, 7, 14 and 21, respectively. Right and left uretronephrectomies were performed and specimens were taken for the histopathological examination. Results revealed significant increases in total leucocytes and neutrophils counts from day 2-17. There were significant decreases (p<0.01) in total RBCs count and PCV% at day 14. Creatinine level was significantly increased on days 7 and 17. Histopathological changes were varied from glomerular swelling and congestion to glomerular atrophy.