Altered levels of pregnancy hormones have been suggested to initiate testicular cancer prenatally in the male fetus. The placenta is the main source of pregnancy hormones, and pregnancy hypertension and preeclampsia are associated with placental malfunction, including altered levels of hormones such as estrogen and human chorionic gonadotropin. We therefore evaluated fetal exposure to pregnancy hypertension and preeclampsia in relation to risk of testicular cancer in adolescent and adult life. We identified 293 cases of germ cell testicular cancer in the Swedish Cancer Register, and 861 controls in the Swedish Medical Birth Register. The standardized antenatal and delivery charts of the cases and controls were traced in the archives of the delivery units, and information about maternal and pregnancy characteristics such as gestational hypertension, proteinuria, anemia, and glucosuria were extracted. Odds ratios (OR) with 95% confidence intervals (CI) were calculated using conditional logistic regression. We found a strongly decreased risk of testicular cancer among subjects exposed to severe gestational hypertension (OR, 0.29; 95% CI, 0.12-0.74, compared with no hypertension), whereas the risk was increased among those exposed to mild gestational hypertension (OR, 1.62; 95% CI, 0.98-2.69) during the fetal period. The mechanism behind the association between pregnancy hypertension and testicular cancer is unclear, but our findings may reflect a potentially protective effect of the altered pregnancy hormones such as human chorionic gonadotropin that occur in severe gestational hypertension and preeclampsia.