Ovarian remnant syndrome (ORS) is the presence of functional ovarian tissue with signs of oestrus as a complication after ovariohysterectomy (OHE) or ovariectomy. Stump pyometra is another complication that can be observed after OHE. However, there are few reports about ORS and stump pyometra in queens. In this report, three queens with recurrent oestrous behaviours after OHE are described. In two queens, ORS with stump pyometra was diagnosed and in one queen ORS alone was diagnosed by physical examination, medical history, vaginal cytology and ultrasonography. Remnant ovarian and uterine tissues were removed by laparotomy. Two queens recovered without any complications; however, one queen died 2 days after surgery. This study reveals that ORS and stump pyometra can result in severe disease and can be fatal.