Abstract Background Testicular cancer survivors often have impaired gonadal function possibly related to chemotherapy. Platinum is a heavy metal that can be detected at low levels in serum many years after treatment, it is not known whether platinum also persists in semen and if platinum persistence in semen is associated with impaired fertility. Methods Adult cisplatin‐treated testicular cancer survivors were enrolled. High‐Performance Liquid Chromatography‐tandem mass spectrometry was used to measure semen and serum platinum levels. Semen quality and DNA Fragmentation Index (DFI) were assessed. Results From 11/2017 to 12/2019, 38 patients (median age 32 years; range: 19–52) were enrolled. Median cumulative cisplatin dose was 301 mg/m2 (range: 274–404). Platinum levels were higher in semen than in blood (p = 0.03). Semen platinum levels were not significantly associated with time from last cisplatin dosing (r = −0.34; p = 0.09) nor cumulative dose (r = −0.10, p = 0.63). Sperm concentration was correlated with time from last cisplatin dosing (r = 0.58, p