Background: Increased risks of SMN after radiotherapy (RT) for testicular cancer (TC) are well established. Few population-based studies, however, have focused on SMN risk among a contemporary group of TCS managed initially with non-RT approaches, including CHEM. Methods: Standardized incidence ratios (SIR) of SMN stratified by site and time since TC diagnosis were calculated for 18,627 TCS reported to the SEER program (1980-2008) who initially had CHEM (n=8,058) or SURG (n=10,569) alone without RT, with each cohort accruing 65,398 and 92,681 person-years (PY) of follow-up respectively. Results: After CHEM, significantly increased risks of solid cancers (n=154; SIR 1.3; 95% CI 1.1-1.5; absolute excess risk (AER) 5.4 per 10,000 PY) and leukemias (n=18, SIR 3.9; 95% CI 2.3-6.1; AER 2.0) were observed. Solid cancer risk remained elevated for > 20 yrs, whereas excess leukemias were concentrated within 10 years after diagnosis. SIRs for solid cancers during the <1, 1-4, 5-9, 10-14, 15-19, and 20+ yr periods were 2.0 (95% CI 1.03-3.5), 1.4 (95% CI 0.97-2.0), 0.8 (95% CI 0.5-1.2), 1.3 (95% CI 0.9-1.8), 1.6 (95% CI 1.05-2.2), and 1.5 (95% CI 0.95-2.2) respectively (P-trend 0.5) whereas SIRs for leukemia were 3.2, 9.9 (P<0.05), 2.6, and 2.3 respectively, with no cases reported in the latter 2 intervals. Median latencies to the development of solid cancers and leukemia were 12.5 yr (0.1-28) and 2.5 yr (0.1-14) respectively. Increased site-specific risks were apparent for cancers of liver (SIR 1.9; 95% CI 0.6-4.4); pancreas (SIR 2.1; 95% CI 0.8-4.6); soft tissue (SIR 4.9; 95% CI 2.1-9.7); bladder (SIR 1.9; 95% CI 1.02-3.3); kidney (SIR 2.6; 95% CI 1.4-4.3); brain/CNS (SIR 1.8; 95% CI 0.7-3.7), and thyroid (SIR 3.9; 95% CI 2.1-6.6). Secondary leukemias included 16 non-lymphocytic and 2 lymphocytic leukemias. In contrast, among TCS managed initially with SURG alone, no excess solid cancers were observed (n=198; SIR 1.0; 95% CI 0.8-1.1), albeit an increased risk of leukemia (n=15; SIR 1.9; 95% CI 1.1-3.2, AER 0.8) was seen. Conclusions: Future analytic studies should further evaluate the site-specific risks of SMN after modern CHEM for TC and the baseline risk among patients managed with non-cytotoxic approaches.