BACKGROUND: To determine histomorphological changes of ureter and kidney following experimental ureteral anastomosis. OBJECTIVES: The aim of this study was to evaluate more details about complications arising from ureteral anastomosis in dogs. METHODS: Five healthy mongrel dogs weighing between 15-30 kg were used. Anesthesia was induced by acepromazine and thiopenthal sodium and maintained by halothane in oxygen in a closed circuit. After midline celiotomy, left ureter near trigon area was incised and immediately end to end anastomosis was performed in simple interrupted pattern by using polydiaxanon 6/0. All animals were euthanized at day 90 after operation and the ureters and their related kidneys were evaluated both macroscopically and microscopically. RESULTS: The gross observations of the ureters showed obstruction (one case) and mild hydroureter (three cases). Microscopically, hyperplasia (in epithelial and muscularis layers), fibrosis (lamina properia-submucosa and serosal layers) and different phases of inflammation and repair (in lamina properia-submucosa, muscularis and serosal layers) were observed in the ureters. Histological sections in the related kidneys revealed hydronephrosis in one case. CONCLUSIONS: Although ureteral anastomosis is technically difficult in small animals and has a high rate of postoperative obstruction,  in case of transected or damaged ureter, ureteral reanastomosis is one of the options for veterinary surgeons. In the present study, in spite of some complications, the anastomosis has been performed successfully in 80 percent of animals and certainly meticulous surgery is mandatory to prevent ureteral obstruction.