As part of a study of long-term survivors of childhood and adolescent cancer, we interviewed 2170 survivors and 3138 sibling control subjects about their marital histories. In a proportional hazards analysis, both male and female survivors were less likely to be ever married than control subjects (rate ratio [RR] for males, 0.87; 99% confidence interval, 0.76 to 0.99; RR for females, 0.86; 99% confidence interval, 0.76 to 0.97). Survivors of brain and central nervous system tumors accounted for most of the marriage deficit, which was greater in men than in women (RRs, 0.48 and 0.73, respectively). Survivors married at the same average age as control subjects, except for survivors of central nervous system tumors, who married slightly later. The average length of first marriages was shorter in survivors than in control subjects. Men who had survived central nervous system tumors diagnosed before 10 years of age and male survivors of retinoblastoma had higher divorce rates than male control subjects (RRs, 2.9 and 1.9, respectively). In this cohort (which received less intense therapy than given in current practice), altered marriage practices are substantial only among survivors of central nervous system tumors.