Granulocytic sarcoma (chloroma) is a mass of malignant myeloid precursor cells in an extramedullary location. The female genital tract, including the ovary, may be the first site for clinical manifestation of granulocytic sarcoma. The MR findings are reported in a case of ovarian granulocytic sarcoma which preceded acute myelogenous leukaemia. Granulocytic sarcoma shows a mixed cystic and solid adnexal mass with intermediate signal intensity on T1 weighted images and hypointensity on T2 weighted images.