ObjectiveTo evaluate sexual function after treatment using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire‐Testicular Cancer 26 (EORTC QLQ‐TC26) questionnaire in Japanese testicular cancer (TC) survivors in a multi‐institutional, cross‐sectional study.MethodsThis study enrolled TC survivors who visited any of eight high‐volume institutions in Japan from 2018 to 2019. After obtaining informed consent, participants completed the EORTC QLQ‐TC26 questionnaires. We evaluated sexual function after treatment for TC using the EORTC QLQ‐TC26 and analyzed the impact of treatment on sexual function in TC survivors.ResultsA total of 567 TC survivors responded to the EORTC QLQ‐TC26. Median age at the time of response was 43 years (interquartile range [IQR] 35–51 years), and median follow‐up period after treatment was 5.2 years (IQR 2.2–10.0 years). Sexual function, particularly ejaculatory function, was significantly lower after post‐chemotherapy retroperitoneal lymph node dissection (PC‐RPLND) than after Surveillance or Chemotherapy groups (p < 0.05). In the PC‐RPLND group, nerve‐sparing procedure preserved postoperative ejaculatory function after RPLND compared with the non‐nerve‐sparing and offered improved ejaculatory function with time. On multivariate analysis, RPLND was a significant predictor of post‐treatment ejaculatory dysfunction, particularly without nerve‐sparing (odds ratio 3.0, 95% CI 1.2–7.7, p < 0.05). In addition, TC survivors with nerve‐sparing RPLND had higher sexual activity than those without.ConclusionThis survey of the EORTC QLQ‐TC26 showed that sexual function and activity in TC survivors after RPLND was reduced in the absence of nerve‐sparing techniques.