Background: Based on only smaller retrospective cohort studies, current guidelines recommend primary retroperitoneal lymph node dissection (RPLND) for men with marker-negative stage 2a non-seminomatous germ cell tumor (NSGCT). We aimed to reassess the role of primary RPLND in marker negative stage 2a, explore results in stages 2b/c and/or marker-positive disease, and evaluate surgical methods, recurrence, and adjuvant chemotherapy indications. Methods: Data from 17 institutions were collected, comprising 305 men who underwent primary RPLND for stage 2 NSGCT. Regression analyses were conducted to predict histology in the RPLND specimen and progression-free survival (PFS). Results: A larger retroperitoneal lymph node diameter was associated with pure teratoma in the RPLND specimen (odds ratio [OR] 1.03, 95% confidence interval [CI] 1.01-1.09, p-value = 0.02), but it did not correlate with PFS. The 5-year PFS rates were 85% for men with pure teratoma, 94% for men with viable cancer who received adjuvant chemotherapy, and 72% for men with viable cancer who did not receive adjuvant chemotherapy. The number of adjuvant chemotherapy cycles did not significantly affect PFS. Conclusions: Our study suggests considering primary RPLND not only in marker negative clinical stage 2a but also marker negative clinical stage 2b. Further research should identify the efficacy in men in other stages (2C or marker positive) and which patients may benefit from adjuvant chemotherapy and the optimal cycle number.