Abstract Objective To assess the prevalence of fertility or infertility in men before and after treatment for unilateral testicular cancer. The results were compared with the lifetime prevalence of infertility in the general population (20%–28%). Design Survey. Setting University referral center for testicular cancer. Patient(s) Two hundred twenty-six patients treated for testicular cancer. Intervention(s) Questionnaire on fertility and fertility-related factors before and after treatment of disease. Main outcome measure(s) Prevalence of fertility before and after treatment for testicular cancer. Result(s) Before the cancer was diagnosed, 79 (66%) of 120 couples who attempted to conceive succeeded within 1 year. After treatment, 38 (43%) of 88 couples conceived within 1 year. Seven couples used cryopreserved sperm to conceive a child after treatment. The different treatment modalities did not significantly influence the outcome of patients’ wish for children. Congenital malformations were recorded in approximately 4% of the children born before or after treatment. Conclusion(s) Although the majority of the patients with testicular cancer have a fulfilled wish with regard to children, it seems to be more difficult to father a child after treatment compared with the case in the general population. Because it is not possible to predict which patient will have fertility problems after treatment, cryopreservation should be offered to every testicular cancer patient. An increased risk for congenital malformations was not observed.