Background The superiority of one course of bleomycin, etoposide, and cisplatin (BEP) over retroperitoneal lymph node dissection (RPLND) as adjuvant treatment in patients with clinical stage I nonseminomatous germ cell tumours (CSI-NSGCT) in terms of recurrence has been shown. However, studies providing validated prospective quality-of-life (QoL) data in patients with CSI-NSGCT treated with only one cycle of BEP are lacking. Objective To examine and compare QoL issues in patients with CSI-NSGCT after adjuvant treatment. Design, setting, and participants Between 1996 and 2005, we randomly assigned a total of 382 patients with CSI-NSGCT to receive either one course of BEP or RPLND after orchiectomy. The European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ-C30) plus additional scales questionnaire (QLQ-C30+) was completed prospectively according to an a priori schedule, with a final assessment in 2011. Outcome measurements and statistical analysis We used the Mann-Whitney U test to detect a difference >17% on the global QoL item "overall strain." Results and limitations Of 382 patients randomised to receive either one course of BEP (n = 191, arm A) or RPLND (n = 191, arm B), completed QLQ-C30+ and data on treatment response were available in 162 and 164 patients, respectively. All participants were included for intention-to-treat analysis. We evaluated treatment-related changes in QoL for the follow-up period up to 3 yr after treatment. We observed no significant differences between the treatment groups in any QoL domain except alopecia. Compared to QoL assessments in the general population, both arms had already recovered to normal values in all items by 6 mo. Conclusions The QoL assessment of this large randomised trial was not able to detect significant differences in QoL scores between patients undergoing RPLND and BEP in a community-based setting. Patient summary Retroperitoneal lymph node dissection and bleomycin, etoposide, and cisplatin are two adjuvant treatment options for patients with CSI-NSGCT after orchiectomy. Quality of life had already recovered to normal levels in both groups by 6 mo after treatment. No clinically relevant differences were detected.