Abstract Objectives To characterize the incidence, presentation, management, and relapse of a large population of bilateral testicular germ cell tumors (TGCT) from a single institution. Methods We identified bilateral TGCT diagnosed between 1/1989 and 2/2014. We categorized synchronous and metachronous TGCT, noting time between 1st and 2nd TGCT, histology seminoma vs. nonseminoma (NSGCT), stage and treatments. Kaplan Meier survival estimates characterized relapse. Results Of 5,132 TGCT patients, 128 (2.5%) had bilateral TGCT. Bilateral TGCT increased over time–1.7% in 1989-1994 up to 3.8% in 2010-2/2014. The 35 (27%) synchronous TGCT had 20 (57%) concordant seminoma, 5 (14%) concordant NSGCT, and 10 (29%) discordant. The 93 (73%) metachronous cases had median time interval to 2nd TGCT of 73 months (range 5 months to 28.6 years). Compared to 1st TGCT, 39 (42%) had discordant histology, 29 (31%) concordant seminoma, and 25 (27%) concordant NSGCT. Stage at 1st tumor was statistically similar to second TGCT (2nd stage I/II/II in 69%/22%/10%). Increasing duration between 1st and 2nd TGCT was not associated with higher stage (II/III) at second TGCT (p=0.09). Treatment at 1st tumor was not associated with stage at 2nd tumor. Relapse following bilateral diagnosis was 16.8% (95%CI 10.5-26.2%) at 5 years. Conclusions Incidence of bilateral TGCT increased with >25% of metachronous TGCT presenting ≥10 years after 1st TGCT; possible causes include increased survivorship and/or referral bias. Stage was statistically similar at 1st and 2nd tumor; stage at 2nd tumor was not associated with time interval between tumors or prior treatment modality at 1st tumor.