Introduction Cancer's impact on family formation in older adulthood is not well described. Marriage rates among older adults were therefore explored. Method Data on the unmarried Norwegian population aged 45-80 in 1974-2001 (N=306 000) was retrieved from the Cancer Registry, the Central Population Register, and population censuses. Marriage rates for 27600 persons diagnosed with cancer were compared to those of the general population by means of discrete-time hazard regression models. Results Men with cancer had a similar marriage rate as cancer-free men, whereas women experienced a 25% marriage deficit after cancer. This deficit was most pronounced after ovarian (OR 0.48) and breast (OR 0.69) cancer. Marriage rates decreased with time from diagnosis. No cancer forms elevated marriage rates. Conclusion Marriage rates among older male cancer survivors are similar to those of the general population. Ovarian and breast cancer in older women was associated with pronounced marriage deficits. A possible explanation is that these gender-specific cancers relate to aspects of persons' psychological well-being, body image, and sense of femininity. Long-term adverse treatment effects are also common for the cancers in question. To explore explanations further, more details on treatment and illness progression are needed. Implications for cancer survivors Increased awareness of how ovarian and breast cancer may affect (prospects of) interpersonal relationships is valuable for cancer survivors and clinicians, and may facilitate communication of relevant, related issues during consultations. Our findings may suggest a need for more extensive psychosocial follow-up after these gender-specific cancer forms in older women, but further research is clearly warranted.