Urethral obstruction in a three-year-old spayed crossbred terrier bitc
h is described. The patient presented after 12 hours of anuria followi
ng a week of dysuria and haematuria. Urethral catheterisation and retr
ograde urethral lavage. were used to retropulse the urethroliths into
the bladder before they were surgically removed. Recovery was uneventf
ul and the calculi were found to be predominantly magnesium ammonium p
hosphate with some calcium oxalate. The management of urolithiasis is
discussed.