The case histories of 175 dogs with ureteral ectopia were reviewed; there were 156 females and 19 males. Golden retrievers, labrador retrievers and Skye terriers appeared to be over-represented. Their median age when examined was 10 months, and the males were significantly older than the females. Fifty-six animals were affected bilaterally, 50 were affected on the left side alone and 69 on the right side alone. One hundred and twenty-two cases had other abnormalities and 67 had more than one; they included hydro-ureter, hydronephrosis, pyelonephritis, bladder hypoplasia and congenital incompetence of the urethral sphincter mechanism. Forty-one cases were not treated, and the other 134 were treated by ureteronephrectomy, extravesicular ureteric transplantation or intravesicular ureteric transplantation. One hundred and twelve cases were available for follow-up for a median period of over two years (range one month to 15 years). The response to surgery and the incidence of complications was similar after each method of treatment. Sixty-five of the 112 cases were cured of incontinence and 26 were improved. The complication rate (14 per cent overall) was similar for each procedure although different types of complications occurred. Hydronephrosis occurred most commonly after extravesicular transplantation and dysuria occurred most commonly after intravesicular transplantation.