The presence of estrogens alone increases the risk of cancer of the endometrium. The risk increases with dosage and length of administration. Estrogens have a promoting rather than an initiating role since the risk progressively disappears after stopping treatment. Hormone-induced cancers have a better prognosis than spontaneous cancers. The association of progesterone or a progestogen obviates this risk. Prescription of oestrogens after treatment of cancer of the endometrium is non longer strictly contraindicated. Each case should be considered independently.