The effects of infertility and its treatment on cancer risk are of concern to many infertile couples. Infertile women appear to be at no higher risk for breast cancer although they may be more at risk for cancers of the uterus, particularly if they have ovulation disorders. Most studies show no increase in the risk of invasive ovarian cancer in infertile women, but ovarian tumours of borderline malignancy are more common. There seems to be no overall increase in cancer risk associated with fertility drug treatment, but questions remain about risk in subgroups of infertile women. Male infertility has been associated with an increased risk of testis cancer. Cancer incidence in children born after fertility treatment appears to be similar to that in the general population. Discussion of cancer risks in the context of other reproductive and community risks can be helpful to patients.