We present the case report of a patient with severe polycythaemia associated with tibolone. In our 65-year-old postmenopausal patient who initially presented with haemoglobin 203 g/L [115-160] and haematocrit 0.63 [0.32-0.47], the cessation of tibolone, a synthetic hormone replacement therapy, led to a dramatic and sustained resolution of this patient's polycythaemia to normal haematological values. Tibolone possesses oestrogenic, androgenic, and progestogenic properties. Tibolone therapy may be an infrequently recognized contributor towards polycythaemia in postmenopausal patients presenting to haematology clinics.