A 3-month-old male entire Bouvier des Flandres was presented for acute onset dysuria, haematuria, lethargy and severe pain on palpation of the penis. Further investigation revealed a parcellar fracture of the cranial separate ossification centre of the os penis and associated urinary tract infection with presumed pyelonephritis. Fluoroscopic retrograde urethrography was performed revealing intermittent urethral obstruction caused by displacement of the cranial bone fragment of the separate ossification centre of the os penis. The urethra was catheterised to re-align the fragments and to permit urination and antibiotic treatment was started. The urinary catheter was kept in place for five days. After its removal, normal urination was observed with complete resolution of the clinical signs. Follow-up radiographs and ultrasound examination confirmed resolution of mechanical obstruction with fusion of part of the separate ossification centre and realignment of the displaced bony fragment.