The authors report a rare case of placenta praevia percreta with bladder invasion giving rise to the need to carry out an emergency hysterectomy in order to stop the bleeding. The literature when analysed showed the possible outcome of this complication in a woman who had already had a caesarean section and who had placenta praevia that required a second caesarean. In this situation it is almost inevitable that a hysterectomy has to be carried out to stop the bleeding. The hysterectomy should be a total hysterectomy but this can be difficult because of the invariable "fusion" that takes place between the uterus and the posterior wall of the bladder. What has to the done bladder can range from simple closure of a hole in the bladder to ureteric diversion with reimplantation of the ureter depending on how badly the bladder has been invaded. In our case after a sub-total hysterectomy had been carried out with simple closure of the bladder, it was necessary to re-operate to treat a fistula between the bladder and the cervix.