Background: As the characteristics and outcome of non-seminomatous testicular germ cell tumours (NSGCT) with teratoma-containing primaries are still under debate, this study aims at evaluating recurrence-free and tumor-specific survival in this cohort of patients. Methods: We performed a retrospective analysis including 218 patients with metastatic NSGCT as a registry study within the "German Testicular Cancer Study Group". We analysed patient characteristics as well as follow-up of all included patients, being treated from 2000 to 2021. Results: Of the eligible 218 patients with NSGCT, 92 (42%) of all orchiectomy specimens had teratoma-containing primaries, while 126 (58%) were teratoma-free. Kaplan-Meier estimates revealed that 28% of all patients relapsed during a median follow-up of 58 months [35-112] with a median time to relapse of 10 months. Teratoma-containing and teratoma-free NSGCT did not show a significant difference regarding the occurrence of relapse, however, teratoma-containing NSGCT had a significantly lower rate of early relapses ( < 24 months) compared to teratoma-free NSGCT (57% vs. 82%, p = 0.035). 14% (30/218) of all patients died due to their disease with a median time to death of 15 months, however median overall survival was not reached. There was no difference regarding the tumour-specific survival between teratoma-containing NSGCT and teratoma-free NSGCT when looking at the entire cohort of patients (11% vs. 16%, p = 0.299). However, in the group of intermediate or poor IGCCCG prognosis patients, tumour-specific survival was significantly worse in patients teratoma-free NSGCT compared to teratoma-containing specimens (16% vs. 35%, p = 0.040). Furthermore, patients with intermediate or poor IGCCCG prognosis showed a higher tumour-related mortality in pure teratoma-free primaries compared to patients with pure teratoma in the orchiectomy specimens (28% vs. 14%, p = 0.070). Here, pure embryonal carcinoma showed the highest relative mortality (80%). Conclusions: In our study, NSGCT patients with teratoma-containing primaries showed a significantly lower number of early relapses as well as a reduced tumour specific survival in intermediate and poor prognosis patients compared to teratoma-free NSGCT. Especially pure embryonal carcinoma patients revealed the highest rate of mortality. Consequently, treating physicians should be aware of these patients portending a dismal prognosis.